Virtual Private Server (VPS) Hosting provided by Central Point Networking cpnllc.com
For some reason, the "Nodelist" and "Recent Callers" features are not working.
| Sysop: | Ray Quinn |
|---|---|
| Location: | Visalia, CA |
| Users: | 50 |
| Nodes: | 10 (0 / 10) |
| Uptime: | 70:50:38 |
| Calls: | 2 |
| Files: | 11,894 |
| Messages: | 148,372 |
Check out the US 99 menu above for links to information about US Highway 99, after which the US 99 BBS is named.
Be sure to click on the Amateur Radio menu item above for packet BBSes, packet software, packet organizations, as well as packet how-to's. Also included is links to local and some not-so-local Amateur Radio Clubs.
As I understand, it is a combination freight and passenger train,
as opposed to just baggage cars for express and mail.
What does that mean for the passengers? Presumably, they
take longer for a trip, but that would be reflected in
the schedule.
At Wed, 12 Dec 2018 17:07:33 -0800 (PST) hancock4@bbs.cpcn.com wrote:
As I understand, it is a combination freight and passenger train,
as opposed to just baggage cars for express and mail.
What does that mean for the passengers? Presumably, they
take longer for a trip, but that would be reflected in
the schedule.
In modern times it would be really small branch line with too little traffic for dedicated passenger *and* freight trains, so one of the local box shifts gets a passenger car hitched up and carries the "handfull" of locals. Often this is someplace too remote for any other sort of transit (eg no roads for a bus or cars, etc.). Sometimes the "freight" is just as "meager" as the passengers -- eg all LCL freight, eg a train with engine, passenger/baggage, a
couple of box cars, and a cabose. I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that there are trains something like this in remote parts of Africa or Asia. There *might* be some of this in some of the more "rural" parts of Europe.
The other is something that goes back to the "earlier" days of railroading (eg
1860s/1870s), pretty much before the idea of dedicated types of trains.
Note: there is something called a "mixed freight", which just a freight train,
but with a mix of car types/freight, as opposed to a unit train (eg a train of
just coal cars or oil tankers or TOFC or containers, etc.).
Trains from Winnipeg to Churchill would probably qualif-i as a mixed
train, as might the train from Sept-|Ales to Schefferville.
John Levine wrote to hounslow3@yahoo.co.uk <=-
The tri-weekly Via train to Churchill (which resumed running all the
way to Churchill last week) is just a passenger train with a baggage
van. Until the washout last year there was a weekly freight train,
which will presumably resume. The new owner is planning to reopen
the deep water port which would greatly increase the demand for
freight service.
I had not heard that line had been washed out.
How did they manage to get
supplies (and people) in and out? Isn't the rail line the only land link
to the rest of Canada?
In article <544879245@f10.n1.z44985.fidonet.org>,
Mike Powell <Mike.Powell@f10.n1.z44985.fidonet.org> wrote:
I had not heard that line had been washed out.
It was in the CBC and provincial news.
How did they manage to get
supplies (and people) in and out? Isn't the rail line the only land link >>to the rest of Canada?
By air, very, very expensively. Churchill has a large deepwater seaport,
but it's been closed for a few years.
John Levine wrote to Mike Powell <=-
I had not heard that line had been washed out.
It was in the CBC and provincial news.
How did they manage to get
supplies (and people) in and out? Isn't the rail line the only land link
to the rest of Canada?
By air, very, very expensively. Churchill has a large deepwater
seaport, but it's been closed for a few years.
John Levine wrote to Mike Powell <=-
>I had not heard that line had been washed out.
JL> It was in the CBC and provincial news.
Thanks. Being in KY, USA, and not having looked lately, I had missed that!
Glad they apparently have it fixed now.
> How did they manage to get
>supplies (and people) in and out? Isn't the rail line the only land link
>to the rest of Canada?
JL> By air, very, very expensively. Churchill has a large deepwater
JL> seaport, but it's been closed for a few years.
That will be a good thing for Churchill, I am sure.
Thanks!
Mike
... Computer Hacker wanted. Must have own axe.
Is the seaport reopening, now that the rail link is back?
They were earlier exporting cereals from the prairies, IIRC.
At Wed, 12 Dec 2018 17:07:33 -0800 (PST) hancock4@bbs.cpcn.com wrote:
As I understand, it is a combination freight and passenger train,
as opposed to just baggage cars for express and mail.
What does that mean for the passengers? Presumably, they
take longer for a trip, but that would be reflected in
the schedule.
In modern times it would be really small branch line with too little traffic for dedicated passenger *and* freight trains, so one of the local box shifts gets a passenger car hitched up and carries the "handfull" of locals. Often this is someplace too remote for any other sort of transit (eg no roads for a bus or cars, etc.). Sometimes the "freight" is just as "meager" as the passengers -- eg all LCL freight, eg a train with engine, passenger/baggage, a
couple of box cars, and a cabose. I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that there are trains something like this in remote parts of Africa or Asia. There *might* be some of this in some of the more "rural" parts of Europe.
On Wednesday, December 12, 2018 at 9:40:11 PM UTC-5, Robert Heller wrote:
At Wed, 12 Dec 2018 17:07:33 -0800 (PST) hancock4@bbs.cpcn.com wrote:
As I understand, it is a combination freight and passenger train,
as opposed to just baggage cars for express and mail.
What does that mean for the passengers? Presumably, they
take longer for a trip, but that would be reflected in
the schedule.
In modern times it would be really small branch line with too little traffic
for dedicated passenger *and* freight trains, so one of the local box shifts
gets a passenger car hitched up and carries the "handfull" of locals. Often this is someplace too remote for any other sort of transit (eg no roads for a
bus or cars, etc.). Sometimes the "freight" is just as "meager" as the passengers -- eg all LCL freight, eg a train with engine, passenger/baggage, a
couple of box cars, and a cabose. I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that there are trains something like this in remote parts of Africa or Asia. There
*might* be some of this in some of the more "rural" parts of Europe.
Thanks for the info.
In the Official Guide of 1954, there were many 'mixed trains' shown
on little branch lines. For whatever reason, they felt it necessary
to mark the train as such.
(Also, a lot of branch lines were served by bus.)
I remember in the 1970s seeing a local freight work a light
branch line. It would be a locomotive hauling one or two
cars. I couldn't imagine how such a service made any money.
The train needed a full screw to flag crossings, do switching,
etc. After deregulation, many of those lines closed or were
turned over to a shortline. The lines I saw were closed.
Had the railroads had their way, many branch lines would have
been abandoned after WW II, or even before the war. The car,
truck, and bus, eliminated the need for such lines. The RDC
kept some lines going for a while, but that only reduced losses,
not make them profitable.
At Sat, 15 Dec 2018 12:19:46 -0800 (PST) hancock4@bbs.cpcn.com wrote:
On Wednesday, December 12, 2018 at 9:40:11 PM UTC-5, Robert Heller wrote:
At Wed, 12 Dec 2018 17:07:33 -0800 (PST) hancock4@bbs.cpcn.com wrote:
As I understand, it is a combination freight and passenger train,
as opposed to just baggage cars for express and mail.
What does that mean for the passengers? Presumably, they
take longer for a trip, but that would be reflected in
the schedule.
In modern times it would be really small branch line with too little traffic
for dedicated passenger *and* freight trains, so one of the local box shifts
gets a passenger car hitched up and carries the "handfull" of locals. Often
this is someplace too remote for any other sort of transit (eg no roads for a
bus or cars, etc.). Sometimes the "freight" is just as "meager" as the passengers -- eg all LCL freight, eg a train with engine, passenger/baggage, a
couple of box cars, and a cabose. I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that
there are trains something like this in remote parts of Africa or Asia. There
*might* be some of this in some of the more "rural" parts of Europe.
Thanks for the info.
In the Official Guide of 1954, there were many 'mixed trains' shown
on little branch lines. For whatever reason, they felt it necessary
to mark the train as such.
(Also, a lot of branch lines were served by bus.)
I remember in the 1970s seeing a local freight work a light
branch line. It would be a locomotive hauling one or two
cars. I couldn't imagine how such a service made any money.
The train needed a full screw to flag crossings, do switching,
etc. After deregulation, many of those lines closed or were
turned over to a shortline. The lines I saw were closed.
Had the railroads had their way, many branch lines would have
been abandoned after WW II, or even before the war. The car,
truck, and bus, eliminated the need for such lines. The RDC
kept some lines going for a while, but that only reduced losses,
not make them profitable.
Right, these were lines with "parallel" roads, so there services moved from steel wheels to rubber wheels (trucks, cars, busses, etc.). This sort of service is really only going to survive where there are no roads -- it is by rail or not at all, like remote parts of (northern) Canada / Alaska or in some
remote "third world" countries (South America, Africa, and Asia).
I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that >> there are trains something like this in remote parts of Africa or Asia. There
*might* be some of this in some of the more "rural" parts of Europe.
In article <7e15ae78-39ca-499b-bf14-747be2f3a486@googlegroups.com>,
<hancock4@bbs.cpcn.com> wrote:
I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that >> there are trains something like this in remote parts of Africa or Asia. There
*might* be some of this in some of the more "rural" parts of Europe.
The only railroad in Alaska is the Alaska RR and I'm reasonbly sure
they don't run mixed trains.
As far as I know the only mixed train left in North America is the
Keewatin Railway between The Pas and Pukatawagan, Manitoba. They
attach a few passenger cars to twice weekly freight trains.
http://www.krcrail.ca/passenger-service
https://www.viarail.ca/en/explore-our-destinations/trains/regional-trains/the-pas-pukatawagan/description
I think the video / TV program included a passenger train, that carried "LCL" >"freight", but I'm thinking it was stuff like bags of grain or dog food and >the like, carried in the baggage car or in a coach/baggage combo car, not >anatual box car. It was along a line serving peole who were "off the grid" / >homesteading / etc. People would to the full shopping ("everything") and then >bringing it all home on the train.
In article <pv3gqo$42g$1@dont-email.me>,
hounslow3@yahoo.co.uk <hounslow3@yahoo.co.uk> wrote:
Is the seaport reopening, now that the rail link is back?
They were earlier exporting cereals from the prairies, IIRC.
The port closed in 2015, apparently because of low usage. You'd think
that with global warming making the season longer, it'd make sense to
reopen it, but the politics are more complex than I understand.
Some
reports say that Saskatchewan farmers want it open because it is
1000km closer than anything else.
that with global warming making the season longer, it'd make sense to
reopen it, but the politics are more complex than I understand.
Do you know exactly what the politics are? Because otherwise I would
Some reports say that Saskatchewan farmers want it open because it is
1000km closer than anything else.
What is their primary market, BTW, China? I would imagine, in that case, >that Vancouver would probably be more suitable.
In article <uomdnZd9C7XP44jBnZ2dnUU7-XPNnZ2d@giganews.com>,
Robert Heller <heller@deepsoft.com> wrote:
I think the video / TV program included a passenger train, that carried "LCL"
"freight", but I'm thinking it was stuff like bags of grain or dog food and >the like, carried in the baggage car or in a coach/baggage combo car, not >anatual box car. It was along a line serving peole who were "off the grid" / >homesteading / etc. People would to the full shopping ("everything") and then
bringing it all home on the train.
That could be the Churchill train, but I'm pretty sure that putting stuff in the baggage car doesn't turn a passenger train into a mixed train.
For another ambiguous situation, consider the Amtrak Autotrain. It
has two engines, 16 passenger cars including sleepers, diners, and
coaches, and 33 auto carrier cars. I don't think anyone calls it a
mixed train.
Their are likely true mixed trains out there, but probably not in North >America (anymore). Probably in remote areas.
In article <pv47jr$dcd$1@dont-email.me>,
hounslow3@yahoo.co.uk <hounslow3@yahoo.co.uk> wrote:
that with global warming making the season longer, it'd make sense to
reopen it, but the politics are more complex than I understand.
Do you know exactly what the politics are? Because otherwise I would
Nope. Why don't you do some research and let us know what you find?
Some reports say that Saskatchewan farmers want it open because it is
1000km closer than anything else.
What is their primary market, BTW, China? I would imagine, in that case,
that Vancouver would probably be more suitable.
This dandy page from the Canadian Grain Commission has the numbers:
https://grainscanada.gc.ca/statistics-statistiques/cge-ecg/cgem-mecg-eng.htm
It depends on the crop. Largest importers of wheat are Japan,
Indonesia, US, Peru, and Nigeria. Durum wheat largely goes to Italy, Algeria, and Morocco. Barley goes to China. Rapeseed goes to China,
Japan, Mexico, and UAE. Soybeans go to China, peas go to India. Wheat
goes all over the place, from Colombia to Japan.
Remember that bulk shipping by sea is incredibly cheap,
so a 1000 mi--- Synchronet 3.17a-Linux NewsLink 1.110
shorter rail trip to the port could more than make up for a much
longer sea trip via Panama.
In article <7e15ae78-39ca-499b-bf14-747be2f3a486@googlegroups.com>,
<hancock4@bbs.cpcn.com> wrote:
I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that >>> there are trains something like this in remote parts of Africa or Asia. There
*might* be some of this in some of the more "rural" parts of Europe.
The only railroad in Alaska is the Alaska RR and I'm reasonbly sure
they don't run mixed trains.
As far as I know the only mixed train left in North America is the
Keewatin Railway between The Pas and Pukatawagan, Manitoba. They
attach a few passenger cars to twice weekly freight trains.
http://www.krcrail.ca/passenger-service
https://www.viarail.ca/en/explore-our-destinations/trains/regional-trains/the-pas-pukatawagan/description
The only railroad in Alaska is the Alaska RR and I'm reasonbly sure
they don't run mixed trains.
I would have thought that they would have, considering that they supply >communities along the rail route.
I would have thought that Winnipeg-Churchill also run mixed trains,
Tshiuetin Rail Transportation, which provides service to >Sept-|Ales-Schefferville?
In article <pv6p1a$fha$1@dont-email.me>,
hounslow3@yahoo.co.uk <hounslow3@yahoo.co.uk> wrote:
The only railroad in Alaska is the Alaska RR and I'm reasonbly sure
they don't run mixed trains.
I would have thought that they would have, considering that they supply >communities along the rail route.
They run freight trains. Why would they fool around with mixed trains?
These days mixed trains only make sense in rare situations: you need a
place that has passenger rail service but no road good enough for
trucks, and that doesn't have enough demand to be worth running separate freight trains.
I would have thought that Winnipeg-Churchill also run mixed trains,
But if you spent 15 seconds looking at the Via Rail web site, you would
know otherwise. They run freight trains for freight and passenger trains
for passengers.
Tshiuetin Rail Transportation, which provides service to >Sept-|Ales-Schefferville?
Look at the web site, hard to tell. They may have a box car they can
attatch to the train but since their network isn't attached to the
national network, they're not set up to move much freight.
But if you spent 15 seconds looking at the Via Rail web site, you would
know otherwise. They run freight trains for freight and passenger trains
for passengers.
It probably depends on how you define "freight" and "freight car". Is a >"baggage car" a "freight car"? Is carrying a 25lb bag of potatoes in a >"baggage car" as "checked baggage" for a passenger in a passenger car on the >same train considered "freight"? Yes, there are all sorts of semantic issues >here...
In article <b42dnTuYcsLSl4rBnZ2dnUU7-LHNnZ2d@giganews.com>,
Robert Heller <heller@deepsoft.com> wrote:
But if you spent 15 seconds looking at the Via Rail web site, you would
know otherwise. They run freight trains for freight and passenger trains >> for passengers.
It probably depends on how you define "freight" and "freight car". Is a >"baggage car" a "freight car"? Is carrying a 25lb bag of potatoes in a >"baggage car" as "checked baggage" for a passenger in a passenger car on the
same train considered "freight"? Yes, there are all sorts of semantic issues
here...
I would be pretty surprised if anyone seriously argued that a baggage
car turns a passenger train into a mixed train. Passenger cars and
freight cars are different and the differences are not subtle -- the
former have heat and power connections and soft suspensions, the
latter don't. If you look at some youtube videos of the Keewatin
train, you can see it's three old Via Rail passenger cars hung on the
end of a freight train. Not clear where the heat is generated but considering where the line is, it must be heated somehow.
latter don't. If you look at some youtube videos of the Keewatin
train, you can see it's three old Via Rail passenger cars hung on the
end of a freight train. Not clear where the heat is generated but
considering where the line is, it must be heated somehow.
Either there is a steam generator car (really old steam heat) or a HEP >generator car -- newer diesel locos lack steam generators and older diesel >locos lack HEP generators and these cars cover these two cases. Both types of >cars were commonly used at different times and places on *regular* passenger >trains for various reasons. No reason not to do the same for a "mixed" train. >I wonder if one of the those "old Via Rail passenger cars" was in fact a steam >generator car or HEP generator car.
In article <L72dnYv8UMYBO4rBnZ2dnUU7-SPNnZ2d@giganews.com>,
Robert Heller <heller@deepsoft.com> wrote:
latter don't. If you look at some youtube videos of the Keewatin
train, you can see it's three old Via Rail passenger cars hung on the
end of a freight train. Not clear where the heat is generated but
considering where the line is, it must be heated somehow.
Either there is a steam generator car (really old steam heat) or a HEP >generator car -- newer diesel locos lack steam generators and older diesel >locos lack HEP generators and these cars cover these two cases. Both types of
cars were commonly used at different times and places on *regular* passenger >trains for various reasons. No reason not to do the same for a "mixed" train.
I wonder if one of the those "old Via Rail passenger cars" was in fact a steam
generator car or HEP generator car.
That's what I would have thought but look at the cars. None of them
look like a steam generator:
https://youtu.be/AkMaHnRUduY?t=85
This wikipedia page even lists the three cars, two coach/baggage and
a snack bar:
https://en.wikipedia.org/wiki/List_of_Via_Rail_rolling_stock
Maybe the train's just cold in the winter.
In article <pv6p1a$fha$1@dont-email.me>,
hounslow3@yahoo.co.uk <hounslow3@yahoo.co.uk> wrote:
The only railroad in Alaska is the Alaska RR and I'm reasonbly sure
they don't run mixed trains.
I would have thought that they would have, considering that they supply
communities along the rail route.
They run freight trains. Why would they fool around with mixed trains?
These days mixed trains only make sense in rare situations: you need a
place that has passenger rail service but no road good enough for
trucks, and that doesn't have enough demand to be worth running separate freight trains.
I would have thought that Winnipeg-Churchill also run mixed trains,
But if you spent 15 seconds looking at the Via Rail web site, you would
know otherwise. They run freight trains for freight and passenger trains
for passengers.
Tshiuetin Rail Transportation, which provides service to
Sept-|a++les-Schefferville?
Look at the web site, hard to tell. They may have a box car they can
attatch to the train but since their network isn't attached to the
national network, they're not set up to move much freight.
I would be pretty surprised if anyone seriously argued that a baggage
car turns a passenger train into a mixed train. Passenger cars and
I guess it depends on whether the "freight" is or is not associated with the passengers. In the case of the Autotrain, the 33 auto carriers are kind of like "baggage", in that the autos in the auto carriers belong to the passengers in the passenger cars -- eg instead of you carrying your bags to the station, your "bags" carry you... :-) It is not like the Autotrain hauls
new cars from the factory or seaport to dealerships or something like that.
The Churchill train (or the Alaska train), the "freight" all belongs to the passengers -- eg it is their procedes from their weekly shopping excursion.
Their are likely true mixed trains out there, but probably not in North America (anymore). Probably in remote areas.
--
Robert Heller -- 978-544-6933
Deepwoods Software -- Custom Software Services http://www.deepsoft.com/ -- Linux Administration Services heller@deepsoft.com -- Webhosting Services
On Saturday, December 15, 2018 at 8:43:44 PM UTC-5, Robert Heller wrote:
I guess it depends on whether the "freight" is or is not associated with the
passengers. In the case of the Autotrain, the 33 auto carriers are kind of like "baggage", in that the autos in the auto carriers belong to the passengers in the passenger cars -- eg instead of you carrying your bags to the station, your "bags" carry you... :-) It is not like the Autotrain hauls
new cars from the factory or seaport to dealerships or something like that.
As I understand it, a 'passenger train' does not normally
carry freight cars. It would carry post office or baggage cars,
which are designed to run with a passenger train. Freight cars
could be attached, but not as efficiently. I don't think freight
cars have such things as tight lock couplers, HEP lines, signal
lines, etc.
I don't know, but it's possible a 'mixed train' may have a rocky ride
due to the freight cars being in the consist.
Amtrak attempted to carry 'express' shipments, but that didn't work
out.
The Churchill train (or the Alaska train), the "freight" all belongs to the passengers -- eg it is their procedes from their weekly shopping excursion.
Their are likely true mixed trains out there, but probably not in North America (anymore). Probably in remote areas.
--
Robert Heller -- 978-544-6933
Deepwoods Software -- Custom Software Services http://www.deepsoft.com/ -- Linux Administration Services heller@deepsoft.com -- Webhosting Services
On Saturday, December 15, 2018 at 8:43:44 PM UTC-5, Robert Heller wrote:
I guess it depends on whether the "freight" is or is not associated with the >> passengers. In the case of the Autotrain, the 33 auto carriers are kind of >> like "baggage", in that the autos in the auto carriers belong to the
passengers in the passenger cars -- eg instead of you carrying your bags to >> the station, your "bags" carry you... :-) It is not like the Autotrain hauls
new cars from the factory or seaport to dealerships or something like that.
As I understand it, a 'passenger train' does not normally
carry freight cars. It would carry post office or baggage cars,
which are designed to run with a passenger train. Freight cars
could be attached, but not as efficiently. I don't think freight
cars have such things as tight lock couplers, HEP lines, signal
lines, etc.
I don't know, but it's possible a 'mixed train' may have a rocky ride
due to the freight cars being in the consist.
Amtrak attempted to carry 'express' shipments, but that didn't work
out.
The Churchill train (or the Alaska train), the "freight" all belongs to the >> passengers -- eg it is their procedes from their weekly shopping excursion. >>
Their are likely true mixed trains out there, but probably not in North
America (anymore). Probably in remote areas.
--
Robert Heller -- 978-544-6933
Deepwoods Software -- Custom Software Services
http://www.deepsoft.com/ -- Linux Administration Services
heller@deepsoft.com -- Webhosting Services
Does Via Rail still use steam heated cars?
--This wikipedia page even lists the three cars, two coach/baggage and
a snack bar:
https://en.wikipedia.org/wiki/List_of_Via_Rail_rolling_stock
Maybe the train's just cold in the winter.
Maybe... The might just go really old school and have kerosene or possibly >propane heaters.
At Wed, 12 Dec 2018 17:07:33 -0800 (PST) hancock4@bbs.cpcn.com wrote:
As I understand, it is a combination freight and passenger train,
as opposed to just baggage cars for express and mail.
What does that mean for the passengers? Presumably, they
take longer for a trip, but that would be reflected in
the schedule.
In modern times it would be really small branch line with too little traffic for dedicated passenger *and* freight trains, so one of the local box shifts gets a passenger car hitched up and carries the "handfull" of locals. Often this is someplace too remote for any other sort of transit (eg no roads for a bus or cars, etc.). Sometimes the "freight" is just as "meager" as the passengers -- eg all LCL freight, eg a train with engine, passenger/baggage, a
couple of box cars, and a cabose. I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that there are trains something like this in remote parts of Africa or Asia. There *might* be some of this in some of the more "rural" parts of Europe.
The other is something that goes back to the "earlier" days of railroading (eg
1860s/1870s), pretty much before the idea of dedicated types of trains.
Note: there is something called a "mixed freight", which just a freight train,
but with a mix of car types/freight, as opposed to a unit train (eg a train of
just coal cars or oil tankers or TOFC or containers, etc.).
On Wednesday, December 12, 2018 at 9:40:11 PM UTC-5, Robert Heller wrote:
At Wed, 12 Dec 2018 17:07:33 -0800 (PST) hancock4@bbs.cpcn.com wrote:
As I understand, it is a combination freight and passenger train,
as opposed to just baggage cars for express and mail.
What does that mean for the passengers? Presumably, they
take longer for a trip, but that would be reflected in
the schedule.
In modern times it would be really small branch line with too little traffic >> for dedicated passenger *and* freight trains, so one of the local box shifts >> gets a passenger car hitched up and carries the "handfull" of locals. Often >> this is someplace too remote for any other sort of transit (eg no roads for a
bus or cars, etc.). Sometimes the "freight" is just as "meager" as the
passengers -- eg all LCL freight, eg a train with engine, passenger/baggage, a
couple of box cars, and a cabose. I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that >> there are trains something like this in remote parts of Africa or Asia. There
*might* be some of this in some of the more "rural" parts of Europe.
The other is something that goes back to the "earlier" days of railroading (eg
1860s/1870s), pretty much before the idea of dedicated types of trains.
Note: there is something called a "mixed freight", which just a freight train,
but with a mix of car types/freight, as opposed to a unit train (eg a train of
just coal cars or oil tankers or TOFC or containers, etc.).
In some checking of the Official Guide of 1954, many branch lines
were served by buses. I _think_ the government forced railroads
to stop that. I know of some local branch lines that had only
buses in the 1950s, yet by the 1970s they were back to buses.
The railroad owned a bus company but apparently had to divest it.
Indeed, I think several railroads had bus subsidiaries.
One wonders what it would be like to ride one of those rural
bus trips back in the 1950s. Probably rather unpleasant--maybe
an old rough riding hot bus, scuzzy people, dusty. The towns
served probably were rough places, perhaps oil fields or
industrial sites. (Maybe I watch too much TCM.)
Curiously, the reference to bus service was always both the
word BUS at the column head, and, the notation, "service provided
by motor bus operating over the public highway" (where else
would a bus run?*)
Anyway, regarding mixed trains, the scheduled speeds were quite
slow, averaging out to 10-20 MPH. From what I've read elsewhere,
not many people rode them. They basically stuck a coach on
a freight train apparently to meet govt regulations.
One listing said the passengers rode in the caboose. How many
people could a caboose hold? I'd think only one or two beyond
the train crew.
On Wednesday, December 12, 2018 at 9:40:11 PM UTC-5, Robert Heller wrote:
At Wed, 12 Dec 2018 17:07:33 -0800 (PST) hancock4@bbs.cpcn.com wrote:
As I understand, it is a combination freight and passenger train,
as opposed to just baggage cars for express and mail.
What does that mean for the passengers? Presumably, they
take longer for a trip, but that would be reflected in
the schedule.
In modern times it would be really small branch line with too little traffic
for dedicated passenger *and* freight trains, so one of the local box shifts
gets a passenger car hitched up and carries the "handfull" of locals. Often this is someplace too remote for any other sort of transit (eg no roads for a
bus or cars, etc.). Sometimes the "freight" is just as "meager" as the passengers -- eg all LCL freight, eg a train with engine, passenger/baggage, a
couple of box cars, and a cabose. I believe I've seen a video/TV program about
such a service running in Alaska in some really remote area. I expect that there are trains something like this in remote parts of Africa or Asia. There
*might* be some of this in some of the more "rural" parts of Europe.
The other is something that goes back to the "earlier" days of railroading (eg
1860s/1870s), pretty much before the idea of dedicated types of trains.
Note: there is something called a "mixed freight", which just a freight train,
but with a mix of car types/freight, as opposed to a unit train (eg a train of
just coal cars or oil tankers or TOFC or containers, etc.).
In some checking of the Official Guide of 1954, many branch lines
were served by buses. I _think_ the government forced railroads
to stop that. I know of some local branch lines that had only
buses in the 1950s, yet by the 1970s they were back to buses.
The railroad owned a bus company but apparently had to divest it.
Indeed, I think several railroads had bus subsidiaries.
One wonders what it would be like to ride one of those rural
bus trips back in the 1950s. Probably rather unpleasant--maybe
an old rough riding hot bus, scuzzy people, dusty. The towns
served probably were rough places, perhaps oil fields or
industrial sites. (Maybe I watch too much TCM.)
Curiously, the reference to bus service was always both the
word BUS at the column head, and, the notation, "service provided
by motor bus operating over the public highway" (where else
would a bus run?*)
Anyway, regarding mixed trains, the scheduled speeds were quite
slow, averaging out to 10-20 MPH. From what I've read elsewhere,
not many people rode them. They basically stuck a coach on
a freight train apparently to meet govt regulations.
One listing said the passengers rode in the caboose. How many
people could a caboose hold? I'd think only one or two beyond
the train crew.
* Red Arrow Lines actually converted a small stretch of an
interurban ROW to a busway. I think it's still there today as
part of SEPTA. It was kind of stupid since a road parallels
it. It is _still_ marked as such on the schedule! http://www.septa.org/schedules/bus/pdf/103.pdf
In some urban areas, there were dedicated bus roads. I believe Boston still >has dedicated *trolley* bus "roads" (actually tunnels connecting between >streets and underground terminals).
In article <GtydnZX4fK4lTLvBnZ2dnUU7-cHNnZ2d@giganews.com>,
Robert Heller <heller@deepsoft.com> wrote:
In some urban areas, there were dedicated bus roads. I believe Boston still >> has dedicated *trolley* bus "roads" (actually tunnels connecting between
streets and underground terminals).
The Harvard Square T station has an underground bus loop used by both
trolley buses and regular buses.
The newish silver line between South Station and the airport uses dual
mode buses that run on overhead wire in the the tunnel and diesel
elsewhere. Next year they're supposed to have new buses that run on batteries on the unwired section.
On 12/28/2018 21:19, John Levine wrote:
The Harvard Square T station has an underground bus loop used by both
trolley buses and regular buses.
The newish silver line between South Station and the airport uses dual
mode buses ...
I missed the beginning of this, but to me and a lot of other folks from >places like San Francisco, a "trolley bus" is simply a bus, like any
other bus (usually large or even articulated) with rubber wheels,
steering wheel, etc., free to go where-ever the driver or happenstance
may direct it, except the powered portions of its trip is limited by the >fact that instead of a smelly diesel engine, it is powered by an
electric motor fed by trolley poles connected to overhead wires ...
The dual-mode buses are what they sound like, trolley buses in the
tunnel, diesel buses outside. The driver puts the poles up or down
when they switch at a bus stop.
In <q085tl$pk0$1@gal.iecc.com> John Levine <johnl@taugh.com> writes:
The dual-mode buses are what they sound like, trolley buses in the
tunnel, diesel buses outside. The driver puts the poles up or down
when they switch at a bus stop.
With the increasing improvement in storage batteries,
would you know of any pseudo trolleys that use overhead
lines where available, and then switch to batteries
for the rest?
The newish silver line between South Station and the airport uses dual
mode buses that run on overhead wire in the the tunnel and diesel
elsewhere. Next year they're supposed to have new buses that run on batteries on the unwired section.
The dual-mode buses are what they sound like, trolley buses in the
tunnel, diesel buses outside. The driver puts the poles up or down
when they switch at a bus stop.
In <q085tl$pk0$1@gal.iecc.com> John Levine <johnl@taugh.com> writes:
The dual-mode buses are what they sound like, trolley buses in the
tunnel, diesel buses outside. The driver puts the poles up or down
when they switch at a bus stop.
With the increasing improvement in storage batteries,
would you know of any pseudo trolleys that use overhead
lines where available, and then switch to batteries
for the rest?
On Saturday, December 29, 2018 at 11:04:07 AM UTC-5, John Levine wrote:
The dual-mode buses are what they sound like, trolley buses in the
tunnel, diesel buses outside. The driver puts the poles up or down
when they switch at a bus stop.
I think NJT's predecessor tried vehicles like that in the 1950s,
but it didn't work out.
hancock4@bbs.cpcn.com wrote to Robert Heller <=-
Curiously, the reference to bus service was always both the
word BUS at the column head, and, the notation, "service provided
by motor bus operating over the public highway" (where else
would a bus run?*)
In <q085tl$pk0$1@gal.iecc.com> John Levine <johnl@taugh.com> writes:
The dual-mode buses are what they sound like, trolley buses in the
tunnel, diesel buses outside. The driver puts the poles up or down
when they switch at a bus stop.
With the increasing improvement in storage batteries,
would you know of any pseudo trolleys that use overhead
lines where available, and then switch to batteries
for the rest?
Thanks
hancock4@bbs.cpcn.com wrote to Robert Heller <=-
ha> Curiously, the reference to bus service was always both the
ha> word BUS at the column head, and, the notation, "service provided
ha> by motor bus operating over the public highway" (where else
ha> would a bus run?*)
IIRC, a couple of short lines in Kentucky actually had rail busses... not RDCs or anything like that, but actual "bus-looking" vehicles powered by
Mack (??) engines with rail wheels on them.
IIRC, a couple of short lines in Kentucky actually had rail busses... not >RDCs or anything like that, but actual "bus-looking" vehicles powered by
Mack (??) engines with rail wheels on them.
They have lots of other self-powered diesel railcars known as DMUs that
are not based on bus designs.
hounslow3@yahoo.co.uk wrote to Mike Powell <=-
IIRC, a couple of short lines in Kentucky actually had rail busses... not RDCs or anything like that, but actual "bus-looking" vehicles powered by Mack (??) engines with rail wheels on them.
Like in Peru?
hounslow3@yahoo.co.uk wrote to Mike Powell <=-
> IIRC, a couple of short lines in Kentucky actually had rail busses... not
> RDCs or anything like that, but actual "bus-looking" vehicles powered by
> Mack (??) engines with rail wheels on them.
>
ho> Like in Peru?
Maybe, I will have to google those.
On 29/12/2018 08:20, Mike Powell wrote:
hounslow3@yahoo.co.uk wrote to Mike Powell <=-
-a > IIRC, a couple of short lines in Kentucky actually had rail
busses... not
-a > RDCs or anything like that, but actual "bus-looking" vehicles
powered by
-a > Mack (??) engines with rail wheels on them.
-a >
-a ho> Like in Peru?
Maybe, I will have to google those.
Similar rail vehicles continue to run in revenue service on Czech
Railways (-iD) and on Railways of the Slovak Republic (++SR).
https://en.wikipedia.org/wiki/-iD_Class_810
IIRC, a couple of short lines in Kentucky actually had rail busses... not RDCs or anything like that, but actual "bus-looking" vehicles powered by
Mack (??) engines with rail wheels on them.
I was recently in Camden, NJ, and was impressed by their
fairly new light rail system using Stadler GTW's. THese
are typically a set of two cars with a small generator
cab/car in between them.
Hmm, I see it's over a decade old and some of the track
is shared with other railroads under a timesharing
agreement.
On Saturday, December 29, 2018 at 4:15:20 PM UTC-5, Mike Powell wrote:
IIRC, a couple of short lines in Kentucky actually had rail busses... not
RDCs or anything like that, but actual "bus-looking" vehicles powered by
Mack (??) engines with rail wheels on them.
Over the years, a variety of light-duty railed vehicles were built
for branch line service, including buses mounted on rail wheels.
The New Haven bought a few Mack units.
The most successful unit was the RDC. Excellent design.
Unfortunately, even though it was much cheaper to operate,
branch line service was still a money-loser in most cases.
If the ground pole comes off, the bus stops...
BUT with no ground, the chassis must float above ground.
Someone boarding or departing would be straddling the voltage
difference; if they stepped into water, or grabbed a handrail...
In article <q0emgi$i3j$1@reader2.panix.com>,
David Lesher <wb8foz@panix.com> wrote:
If the ground pole comes off, the bus stops...
BUT with no ground, the chassis must float above ground.
Someone boarding or departing would be straddling the voltage
difference; if they stepped into water, or grabbed a handrail...
It is my impression that trolleybuses can go either way under the
wire, so I doubt they tie either side to the chassis.
They ran between Brewster North (now Southeast) and Dover Plains, on the >Harlem Line, as well as between Suffern and Port Jervis on the Port
Jervis Line.
hancock4@bbs.cpcn.com wrote to Mike Powell <=-
The most successful unit was the RDC. Excellent design.
Unfortunately, even though it was much cheaper to operate,
branch line service was still a money-loser in most cases.
They were good trains, the Budd cars were.
They ran between Brewster North (now Southeast) and Dover Plains, on the >Harlem Line, as well as between Suffern and Port Jervis on the Port
Jervis Line.
BC Rail also ran them before ending passenger service, IIRC, whilst VIA
Rail Canada ran them between Halifax and Sydney.
Anybody else?
In <q0emss$2bf$1@dont-email.me> "hounslow3@yahoo.co.uk" <hounslow3@yahoo.co.uk> writes:
They ran between Brewster North (now Southeast) and Dover Plains, on the
Harlem Line, as well as between Suffern and Port Jervis on the Port
Jervis Line.
I used to take the train from Pawling to NYC.
I think... think... I remember some Budd Cars actaully
making the whole treck to Grand Central without us
having to transfer.
I might be mistaken, but this would have been
sometime between 1964 and 1972 or so.
No guarantee my memory is correct. In any event,
if it did occur, it would have been pretty rare.
hancock4@bbs.cpcn.com wrote to Mike Powell <=-
ha> The most successful unit was the RDC. Excellent design.
ha> Unfortunately, even though it was much cheaper to operate,
ha> branch line service was still a money-loser in most cases.
I like the RDCs and the idea of one. I wish they had been more successful.
They would have been great for the branch lines.
... DalekDOS v(overflow): (I)Obey (V)ision impaired (E)xterminate
On 31/12/2018 21:00, hancock4@bbs.cpcn.com wrote:
On Saturday, December 29, 2018 at 4:15:20 PM UTC-5, Mike Powell wrote:
IIRC, a couple of short lines in Kentucky actually had rail busses... not >>> RDCs or anything like that, but actual "bus-looking" vehicles powered by >>> Mack (??) engines with rail wheels on them.
Over the years, a variety of light-duty railed vehicles were built
for branch line service, including buses mounted on rail wheels.
The New Haven bought a few Mack units.
The most successful unit was the RDC. Excellent design.
Unfortunately, even though it was much cheaper to operate,
branch line service was still a money-loser in most cases.
They were good trains, the Budd cars were.
They ran between Brewster North (now Southeast) and Dover Plains, on the Harlem Line, as well as between Suffern and Port Jervis on the Port
Jervis Line.
BC Rail also ran them before ending passenger service, IIRC, whilst VIA
Rail Canada ran them between Halifax and Sydney.
Anybody else?
On 31/12/2018 21:00, hancock4@bbs.cpcn.com wrote:
On Saturday, December 29, 2018 at 4:15:20 PM UTC-5, Mike Powell wrote:
IIRC, a couple of short lines in Kentucky actually had rail busses...
not RDCs or anything like that, but actual "bus-looking" vehicles
powered by Mack (??) engines with rail wheels on them.
Over the years, a variety of light-duty railed vehicles were built for
branch line service, including buses mounted on rail wheels.
The New Haven bought a few Mack units.
The most successful unit was the RDC. Excellent design. Unfortunately,
even though it was much cheaper to operate,
branch line service was still a money-loser in most cases.
They were good trains, the Budd cars were.
They ran between Brewster North (now Southeast) and Dover Plains, on the Harlem Line, as well as between Suffern and Port Jervis on the Port
Jervis Line.
BC Rail also ran them before ending passenger service, IIRC, whilst VIA
Rail Canada ran them between Halifax and Sydney.
Anybody else?
On 31/12/2018 21:00, hancock4@bbs.cpcn.com wrote:
On Saturday, December 29, 2018 at 4:15:20 PM UTC-5, Mike Powell wrote:
IIRC, a couple of short lines in Kentucky actually had rail busses... not >> RDCs or anything like that, but actual "bus-looking" vehicles powered by >> Mack (??) engines with rail wheels on them.
Over the years, a variety of light-duty railed vehicles were built
for branch line service, including buses mounted on rail wheels.
The New Haven bought a few Mack units.
The most successful unit was the RDC. Excellent design.
Unfortunately, even though it was much cheaper to operate,
branch line service was still a money-loser in most cases.
They were good trains, the Budd cars were.
They ran between Brewster North (now Southeast) and Dover Plains, on the Harlem Line, as well as between Suffern and Port Jervis on the Port
Jervis Line.
BC Rail also ran them before ending passenger service, IIRC, whilst VIA
Rail Canada ran them between Halifax and Sydney.
Anybody else?
hancock4@bbs.cpcn.com wrote to Mike Powell <=-
The most successful unit was the RDC. Excellent design.
Unfortunately, even though it was much cheaper to operate,
branch line service was still a money-loser in most cases.
I like the RDCs and the idea of one. I wish they had been more successful.
They would have been great for the branch lines.
I like the RDCs and the idea of one. I wish they had been more successful.
They would have been great for the branch lines.
I take it that you've never seen the SPV-2000, which Budd built as a successor to the RDC?
In a word, these units were a lesson of how ***not*** to build a rail car.
Anybody else?
I've often wondered about one aspect of trolley-bus technology.
You have a hot pole, and a ground pole. (I believe on some
routes, the hot cat can also serve railed/streetcar vehicles,
but I'm not sure.)
If the hot pole comes off the cat, the bus stops dead.
If the ground pole comes off, the bus stops...
BUT with no ground, the chassis must float above ground.
Someone boarding or departing would be straddling the voltage
difference; if they stepped into water, or grabbed a handrail...
I can think of a few solutions to the bus issue; I just wonder how
it's actually handled.
(I recall reading of a similar fatality in the Princeton area;
she was boarding or disembarking from an Amtrak train, and an
Acela went by at high speed on a parallel track. That raised
train-ground to well above station ground; she was the conductor
between them.)
On Tuesday, January 1, 2019 at 2:34:47 PM UTC-5, houn...@yahoo.co.uk wrote:
I like the RDCs and the idea of one. I wish they had been more successful. >>> They would have been great for the branch lines.
I take it that you've never seen the SPV-2000, which Budd built as a
successor to the RDC?
In a word, these units were a lesson of how ***not*** to build a rail car.
I rode the SPV a few times and it was ok.
However, they had a very poor reliability record.
I'm not sure what went wrong. Budd had extensive experience
with the RDC and certainly knew how to build a reliable
self-powered train. I don't know what they did differently
on the SPV that made that a failure.
(I recall reading of a similar fatality in the Princeton area;
she was boarding or disembarking from an Amtrak train, and an
Acela went by at high speed on a parallel track. That raised
train-ground to well above station ground; she was the conductor
between them.)
I've often wondered about one aspect of trolley-bus technology.
You have a hot pole, and a ground pole. (I believe on some
routes, the hot cat can also serve railed/streetcar vehicles,
but I'm not sure.)
If the hot pole comes off the cat, the bus stops dead.
If the ground pole comes off, the bus stops...
BUT with no ground, the chassis must float above ground.
Someone boarding or departing would be straddling the voltage
difference; if they stepped into water, or grabbed a handrail...
I can think of a few solutions to the bus issue; I just wonder how
it's actually handled.
(I recall reading of a similar fatality in the Princeton area;
she was boarding or disembarking from an Amtrak train, and an
Acela went by at high speed on a parallel track. That raised
train-ground to well above station ground; she was the conductor
between them.)
David Lesher <wb8foz@panix.com> wrote:
I've often wondered about one aspect of trolley-bus technology.
You have a hot pole, and a ground pole. (I believe on some
routes, the hot cat can also serve railed/streetcar vehicles,
but I'm not sure.)
If the hot pole comes off the cat, the bus stops dead.
If the ground pole comes off, the bus stops...
BUT with no ground, the chassis must float above ground.
Someone boarding or departing would be straddling the voltage
difference; if they stepped into water, or grabbed a handrail...
I can think of a few solutions to the bus issue; I just wonder how
it's actually handled.
(I recall reading of a similar fatality in the Princeton area;
she was boarding or disembarking from an Amtrak train, and an
Acela went by at high speed on a parallel track. That raised
train-ground to well above station ground; she was the conductor
between them.)
One method used at least on some networks is to have the OHL voltage float
so neither wire is directly grounded. My understanding is trolleybuses are designed with the intention of fully insulating the bus from the traction supply rather than using it for grounding, and attempting to ground the vehicle to the road as best as is possible.
Robin
In article <q0emgi$i3j$1@reader2.panix.com>,
David Lesher <wb8foz@panix.com> wrote:
(I recall reading of a similar fatality in the Princeton area;
she was boarding or disembarking from an Amtrak train, and an
Acela went by at high speed on a parallel track. That raised
train-ground to well above station ground; she was the conductor
between them.)
I grew up in Princeton and never heard of such an incident. The only electrical injury I know of is a student who climbed up on top of the
parked Dinky one night in 1990, grabbed the wire, and was nearly killed. It led to a court case where the student got a lot of money from the
railroad and the university. The guy went on to med school and specializes in hospice care:
https://www.ucsfhealth.org/doctors_and_clinics/features/miller_bj/index.html
(I recall reading of a similar fatality in the Princeton area;
she was boarding or disembarking from an Amtrak train, and an
Acela went by at high speed on a parallel track. That raised
train-ground to well above station ground; she was the conductor
between them.)
I grew up in Princeton and never heard of such an incident. The only >electrical injury I know of is a student who climbed up on top of the
parked Dinky one night in 1990, grabbed the wire, and was nearly killed.
I question that. Given the extensive service of a trackless,
sooner or late those circumstances would occur and someone
get zapped. But I don't think that has ever happened.
I can think of a few solutions to the bus issue; I just wonder how
it's actually handled.
John Levine <johnl@taugh.com> writes:
I grew up in Princeton and never heard of such an incident. ...
I can't recall or cite details. But as an EE, it made sense to
me. ...
John Levine <johnl@taugh.com> writes:
I grew up in Princeton and never heard of such an incident. The only >electrical injury I know of is a student who climbed up on top of the >parked Dinky one night in 1990, grabbed the wire, and was nearly killed.
I can't recall or cite details. But as an EE, it made sense to
me. The rails are not grounded through the roadbed as they run,
they are instead isolated by a choke (Wee-Z Bond) and grounded
at the substation. So drawing a lot of current would raise
the rail-to-ground voltage. And thus the train would be above
ground. Usually that's no issue as the train is not drawing high
current. But when the adjacent train is.....
I'm not denying that something like that could happen. I'm
just saying that there's no evidence that it actually has.
Rails aren't grounded through the roadbed?
In <c60fa514-d13f-48d6-aaf2-d2ebbc5531d5@googlegroups.com> hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
Partially but far from entirely. Can't comment directly
to Amtra[c]k and the commuter rails, but in the NYC subway
system there Big and Thick and Heavy copper cables that
help ground the tracks.
I'm not sure just where the the other ends connect up.
A frequent problem is that the copper thieves, or at least
the smarter ones [a], cut into/steal them for the metal.
When this happens, the next time a train comes through
all sorts of ugly electrical stuff occurs and the safeties
shut down power to the third rail, etc.
[a] the dumber ones get Darwin Awards.
Rails aren't grounded through the roadbed?
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com> writes:
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
Huh? I'll agree that a hefty chunk of the current goes back
to, well, somewhere... but it would be damn tricky to isolate
metal tracks from ground.
There are a gazillion metal plates and spikes fastning
the track to, well, the ground. Even if they've got
rubber padding (which sure ain't universal) there's plenty
of metal to metal to ground connectivity.
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com>
writes:
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
Huh?-a I'll agree that a hefty chunk of the current goes back
to, well, somewhere...-a but it would be damn tricky to isolate
metal tracks from ground.
There are a gazillion metal plates and spikes fastning
the track to, well, the ground.-a Even if they've got
rubber padding (which sure ain't universal) there's plenty
of metal to metal to ground connectivity.
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for
domestic electricity. Didn't Edison have a complex set of heavy return (ground) wiring to maintain in lower Manhattan, and wasn't that part of
what killed DC.
I'd love to have non-insulting comments. If I'm wrong, tell me,
politely. If I'm somewhat right, an affirmation would be nice.
Cheers,
DAVe
On 1/9/2019 00:09, spsfman wrote:
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com>
writes:
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
Huh?-a I'll agree that a hefty chunk of the current goes back
to, well, somewhere...-a but it would be damn tricky to isolate
metal tracks from ground.
There are a gazillion metal plates and spikes fastning
the track to, well, the ground.-a Even if they've got
rubber padding (which sure ain't universal) there's plenty
of metal to metal to ground connectivity.
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for domestic electricity. Didn't Edison have a complex set of heavy return (ground) wiring to maintain in lower Manhattan, and wasn't that part of what killed DC.
I'd love to have non-insulting comments. If I'm wrong, tell me,
politely. If I'm somewhat right, an affirmation would be nice.
Cheers,
DAVe
I am not sure how railroads and elevators and such do it now but I
suspect there are as many standards as there are governing boards.
But there are some things I am pretty sure of.
One is that builders of transmission facilities HATE buying copper so if there is no reason not to, one of the conductors in the system will be Earth, AC, DC, or RF.
When I was a little kid, people who lived on streets with street cars
had (I think I remember) corrosion problems with buried metal stiff like water pipes. (What I am sure I remember is later we had a house on a
street where every house wit a streetlamp near the water meter had to replace the water pipe every ten years or make extraordinary repairs.)
We did not have any electric trains and the signal systems were base on Wheatstone bridges which were balanced (I think) for the "no train
present" condition on the rails which were bonded longitudinally but not
(as far as I could tell) isolated from ground except by the
creosote-soaked sleepers. Some signals and controls were activated by engine-whistle-microphone links.
AS regards the original trolley bus connection lethality question, I
still don't know the answer but I think if it were mine to solve I would provide and on-board battery to provide for lights, controls and such, recharged but trolley power when available. I would have the
high-voltage part of the system isolated from the bus body, and probably arrange for the poles to be disconnected from the wires electrically if
the doors are open.
Does the presence of poles imply DC service? Why?
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com>
writes:
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
Huh?-a I'll agree that a hefty chunk of the current goes back
to, well, somewhere...-a but it would be damn tricky to isolate
metal tracks from ground.
There are a gazillion metal plates and spikes fastning
the track to, well, the ground.-a Even if they've got
rubber padding (which sure ain't universal) there's plenty
of metal to metal to ground connectivity.
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for
domestic electricity. Didn't Edison have a complex set of heavy return (ground) wiring to maintain in lower Manhattan, and wasn't that part of
what killed DC.
I'd love to have non-insulting comments. If I'm wrong, tell me,
politely. If I'm somewhat right, an affirmation would be nice.
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com> writes:
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
Huh? I'll agree that a hefty chunk of the current goes back
to, well, somewhere... but it would be damn tricky to isolate
metal tracks from ground.
There are a gazillion metal plates and spikes fastning
the track to, well, the ground. Even if they've got
rubber padding (which sure ain't universal) there's plenty
of metal to metal to ground connectivity.
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for
domestic electricity. Didn't Edison have a complex set of heavy return (ground) wiring to maintain in lower Manhattan, and wasn't that part of
what killed DC.
On 1/9/2019 00:09, spsfman wrote:Unfortunately, using the ground as a return is a poor medium,
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com>
writes:
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
Huh?-a I'll agree that a hefty chunk of the current goes back
to, well, somewhere...-a but it would be damn tricky to isolate
metal tracks from ground.
There are a gazillion metal plates and spikes fastning
the track to, well, the ground.-a Even if they've got
rubber padding (which sure ain't universal) there's plenty
of metal to metal to ground connectivity.
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for domestic electricity. Didn't Edison have a complex set of heavy return (ground) wiring to maintain in lower Manhattan, and wasn't that part of what killed DC.
I'd love to have non-insulting comments. If I'm wrong, tell me,
politely. If I'm somewhat right, an affirmation would be nice.
Cheers,
DAVe
I am not sure how railroads and elevators and such do it now but I
suspect there are as many standards as there are governing boards.
But there are some things I am pretty sure of.
One is that builders of transmission facilities HATE buying copper so if there is no reason not to, one of the conductors in the system will be Earth, AC, DC, or RF.
When I was a little kid, people who lived on streets with street carsOur trolley company had detector vehicles that looked for leaks, so
had (I think I remember) corrosion problems with buried metal stiff like water pipes. (What I am sure I remember is later we had a house on a
street where every house wit a streetlamp near the water meter had to replace the water pipe every ten years or make extraordinary repairs.)
We did not have any electric trains and the signal systems were base on Wheatstone bridges which were balanced (I think) for the "no trainI never heard of an "engine whistle microphone" link. Until relatively recently, microphone and detector technology was not good enough to
present" condition on the rails which were bonded longitudinally but not
(as far as I could tell) isolated from ground except by the
creosote-soaked sleepers. Some signals and controls were activated by engine-whistle-microphone links.
AS regards the original trolley bus connection lethality question, IFor nearly 100 years electric vehicles had a battery to supply
still don't know the answer but I think if it were mine to solve I would provide and on-board battery to provide for lights, controls and such, recharged but trolley power when available. I would have the
high-voltage part of the system isolated from the bus body, and probably arrange for the poles to be disconnected from the wires electrically if
the doors are open.
Does the presence of poles imply DC service? Why?I think poles could be used for either AC or DC service. I
On Wednesday, January 9, 2019 at 11:39:01 AM UTC-5, Larry Sheldon wrote:
On 1/9/2019 00:09, spsfman wrote:
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com>
writes:
hancock4@bbs.cpcn.com writes:
We did not have any electric trains and the signal systems were base on
Wheatstone bridges which were balanced (I think) for the "no train
present" condition on the rails which were bonded longitudinally but not
(as far as I could tell) isolated from ground except by the
creosote-soaked sleepers. Some signals and controls were activated by
engine-whistle-microphone links.
I never heard of an "engine whistle microphone" link. Until relatively recently, microphone and detector technology was not good enough to accurately discern real from false signals. Signals had to be highly reliable.
On 1/9/2019 15:15, hancock4@bbs.cpcn.com wrote:
On Wednesday, January 9, 2019 at 11:39:01 AM UTC-5, Larry Sheldon wrote:
On 1/9/2019 00:09, spsfman wrote:
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com>
writes:
hancock4@bbs.cpcn.com writes:
<gobble on>
<gobble off>
We did not have any electric trains and the signal systems were base on
Wheatstone bridges which were balanced (I think) for the "no train
present" condition on the rails which were bonded longitudinally but not >>> (as far as I could tell) isolated from ground except by the
creosote-soaked sleepers.-a Some signals and controls were activated by
engine-whistle-microphone links.
I never heard of an "engine whistle microphone" link.-a Until relatively
recently, microphone and detector technology was not good enough to
accurately discern real from false signals.-a Signals had to be highly
reliable.
I am pretty sure I have over my 80 summers seen several examples but one
I remember with clarity was at Southern Pacific's station on their
Peninsula
line.-a Eastbound trains stopped at the station just west of the
Sunnyvale Avenue crossing and the crossing guards would time out and
rise, clearing the crossing.-a There was a microphone on a box on a pole that allowed the train to whistle the arms back down.-a (I don't know if
the lash-up had enough intelligence to listen for long long short long
or just loud.-a I AM pretty sure that the spare engine that parked on a siding there could whistle down the arms.
On Wednesday, January 9, 2019 at 1:09:39 AM UTC-5, spsfman wrote:
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com> writes:
hancock4@bbs.cpcn.com writes:
Rails aren't grounded through the roadbed?
No. They are isolated from ground; the return currents go via
those cables Danny mentioned through a Wee_Z bond low pass
filter to the substation. That's so the signaling system will
work.
Huh? I'll agree that a hefty chunk of the current goes back
to, well, somewhere... but it would be damn tricky to isolate
metal tracks from ground.
There are a gazillion metal plates and spikes fastning
the track to, well, the ground. Even if they've got
rubber padding (which sure ain't universal) there's plenty
of metal to metal to ground connectivity.
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for domestic electricity. Didn't Edison have a complex set of heavy return (ground) wiring to maintain in lower Manhattan, and wasn't that part of what killed DC.
Originally, telegraph lines used a single conductor with ground
as the return. That worked reasonably well. When they went to
teleprinters and carrier, they needed better transmission
and switched to metallic circuits.
When the telephone came out, that too used a single conductor
and ground return, but the transmission quality was very poor.
So early on they switched to metallic circuits, too.
At Wed, 9 Jan 2019 13:09:29 -0800 (PST) hancock4@bbs.cpcn.com wrote:
On Wednesday, January 9, 2019 at 1:09:39 AM UTC-5, spsfman wrote:
On 1/8/2019 7:41 PM, danny burstein wrote:
In <q13lao$6pe$2@reader2.panix.com> David Lesher <wb8foz@panix.com> writes:
hancock4@bbs.cpcn.com writes:
When the telephone came out, that too used a single conductor
and ground return, but the transmission quality was very poor.
So early on they switched to metallic circuits, too.
What is going on here is with twisted pair and/or "balanced" circuits is noise cancellation and improving signal-to-noise ratios. This is a different problem from bulk power transmission.
I am not sure how railroads and elevators and such do it now but IFor very low current applications like telephone you can just about get away with it, but for something like railway traction, the current involved is sufficiently high that the electrolytic corrosion from earth-return is extremely damaging. Modern on-street tramways have quite strict rules about how much earth leakage current is permissible. This kind of electrolytic corrosion is much less of a problem with AC systems.
suspect there are as many standards as there are governing boards.
But there are some things I am pretty sure of.
One is that builders of transmission facilities HATE buying copper so if there is no reason not to, one of the conductors in the system will be Earth, AC, DC, or RF.
When I was a little kid, people who lived on streets with street cars
had (I think I remember) corrosion problems with buried metal stiff like water pipes. (What I am sure I remember is later we had a house on a
street where every house wit a streetlamp near the water meter had to replace the water pipe every ten years or make extraordinary repairs.)
AS regards the original trolley bus connection lethality question, IThat all seems like a pretty sensible design concept. Add in some attempt to make as good an earth connection to the road surface too.
still don't know the answer but I think if it were mine to solve I would provide and on-board battery to provide for lights, controls and such, recharged but trolley power when available. I would have the
high-voltage part of the system isolated from the bus body, and probably arrange for the poles to be disconnected from the wires electrically if
the doors are open.
Does the presence of poles imply DC service? Why?Not necessarily. Pretty much all on-street systems are DC, though (with a few exceptions, for example the Chur-Arosa line in Switzerland running through the streets of Chur). DC is much easier to handle on board in terms of controlling the power. The reason not to use DC is to allow a much higher OHL voltage, which allows the feeders and substations to be significantly further apart. Most mainline railways have converged on 25 kV as the right balance of safety and economics, but plenty of legacy systems remain. For on-street running, though, anything more than 1 kV is going to have serious safety implications, which is why most systems both streetcar and trolleybus run somewhere in the 500 - 750 V region. At that voltage there is really no advantage to using AC, but using AC adds complexity to the vehicle. Hence DC is favoured.
Huh? I'll agree that a hefty chunk of the current goes back
to, well, somewhere... but it would be damn tricky to isolate
metal tracks from ground.
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for
domestic electricity. Didn't Edison have a complex set of heavy return >(ground) wiring to maintain in lower Manhattan, and wasn't that part of
what killed DC.
I'd love to have non-insulting comments. If I'm wrong, tell me,
politely. If I'm somewhat right, an affirmation would be nice.
spsfman <spsffan@hotmail.com> writes:Sorry for the copious snippage. I think you're rather mixing up the timeline. Tesla invented the AC induction motor in the 1880s. DC railway electrification became a practical proposition in the 1880s. Early (low frequency) AC followed about 20 years later, but mains frequency wasn't viable until the 1960s. All of these used DC motors. The use of induction motors in railway traction didn't become viable until the 1980s, a full century after Tesla invented them.
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for >domestic electricity. Didn't Edison have a complex set of heavy return >(ground) wiring to maintain in lower Manhattan, and wasn't that part of >what killed DC.
I'd love to have non-insulting comments. If I'm wrong, tell me,
politely. If I'm somewhat right, an affirmation would be nice.
In the early days, AC & DC each held aces.
For DC, it was we knew how to make DC motors that worked.
For AC, we didn't know how to make AC motors.
Enter an under-sung genius, Nikola Tesla. He made the first
viable AC motors. Game Over.
Tesla's motors were fixed speed; set by the line frequency
On Friday, 11 January 2019 06:34:07 UTC+1, David Lesher wrote:
spsfman <spsffan@hotmail.com> writes:
Perhaps my understanding is way off, but, with DC, doesn't the ground
have to return to the source rather than just to the actual earth,
doesn't it?
It was my simple understanding that with AC that wasn't necessary but
with DC it was. That was one of the reasons AC won out over DC for
domestic electricity. Didn't Edison have a complex set of heavy return
(ground) wiring to maintain in lower Manhattan, and wasn't that part of
what killed DC.
I'd love to have non-insulting comments. If I'm wrong, tell me,
politely. If I'm somewhat right, an affirmation would be nice.
In the early days, AC & DC each held aces.
For DC, it was we knew how to make DC motors that worked.
For AC, we didn't know how to make AC motors.
Enter an under-sung genius, Nikola Tesla. He made the first
viable AC motors. Game Over.
Tesla's motors were fixed speed; set by the line frequency
Sorry for the copious snippage. I think you're rather mixing up the timeline.
Tesla invented the AC induction motor in the 1880s. DC railway electrification became a practical proposition in the 1880s. Early (low frequency) AC followed about 20 years later, but mains frequency wasn't viable until the 1960s. All of these used DC motors. The use of induction motors in railway traction didn't become viable until the 1980s, a full century after Tesla invented them.
DC motors have their output controlled by voltage. AC motors have their output determined by the voltage to an extent and by the difference between the rotational speed and the supply frequency, in an annoyingly non-linear fashion.
Early DC motors had a mix of resistances and series/parallel switching for control. Early AC wired the field coils in series with the armature on a DC motor and treated the AC as "psuedo" DC. This doesn't work at mains frequency because of inductance effects, but at lower frequency you can get away with it. This is why the orginal PRR system went with 25 Hz and the De/At/CH system uses 16.7 Hz. Control can be acheived using tap changers.
In the 1960s rectifiers with the power needed for a locomotive and the robustness to survive a railway locomotive environment became small and light enough to fit on one. At that point mains frequency AC became viable, again using tap changers and DC motors for control. In the 1970s power electronics scaled up to the needed power requirements and clever things like choppers and thyristors replaced resistances or tap changers.
In the 1980s power electronics and microprocessor control developed to the point where a DC supply could be converted to a 3 phase AC supply where both the voltage and frequency can be readily controlled, in a package that can fit on a locomotive or multiple unit. It was this key advance that allowed AC motors to replace DC motors. This is now standard.
Incidentally the same VVVF 3 phase supply is what is used on modern "AC" diesel electric locomotives. Because the output of the traction motor is closely related to the difference between the inverter frequency and the rotational speed of the motor, it allows really close control over the traction motors, allowing things like creep control (making the wheels rotate just a tiny bit faster than the road speed dictates) that gives good heavy haul performance.
Robin
First time I have an explanation for 25 Hz power that made sense.
In the Official Guide of 1954, there were many 'mixed trains' shown
on little branch lines. For whatever reason, they felt it necessary
to mark the train as such.
This sounds peculiar to 600 or 750V DC third rail systems. 12 or 25Kv
AC systems with catenary doubtles have different issues and much lower >current.
On Friday, January 11, 2019 at 3:29:23 PM UTC-5, Larry Sheldon wrote:25 Hz was a common mains frequency in the first half of the C20th. When the modern power grids established themselves, the 60 Hz (or 50 Hz depending on region) became established. If the PRR system had no frequency issues, it is likely they would have converted simply for the sake of standardisation. The reason that they didn't was the rolling stock wasn't able at the time to accept higher frequency. Now, pretty much all of the "needs low frequency" rolling stock is retired, but considering the lifetime of things like the GG1 and similar vintage vehicles, by the time the need for low frequency was passed, the capital for railway investment was less available.
First time I have an explanation for 25 Hz power that made sense.
25Hz was popular about 100 years ago. I think the power companies
supplied it. Then well-regulated 60 Hz became the standard, but
for years, power companies had to keep supplying 25 Hz since
many industrial users has 25 Hz motors. Also, some had to supply
DC since older customers had DC motors.
The former PRR NEC remains 25 Hz.
This sounds peculiar to 600 or 750V DC third rail systems. 12 or 25Kv
AC systems with catenary doubtles have different issues and much lower >>current.
Err, lower current? An Acela trainset draws ?15-20 Megawatts I think.
Even at 12.5 KV, that's a few Amperes.
John Levine <johnl@taugh.com> writes:
20 MW at 12.5 kV is 1.6 kA. At 750 V, 1.6 kA provides 1.2 MW, or about 1600 hp. For streetcars or trolleybuses that's plenty. For a metro train or commuter rail, that's not going to offer much. For modern railway applications, 12.5 kV is a bit low voltage these days.This sounds peculiar to 600 or 750V DC third rail systems. 12 or 25Kv
AC systems with catenary doubtles have different issues and much lower >current.
Err, lower current? An Acela trainset draws ?15-20 Megawatts I think.
Even at 12.5 KV, that's a few Amperes.
Eurostars were significantly limited in power on the 3rd rail, as the supply could only offer something like a third of the power available on 25 kV. The only reason the UK southern 3rd rail system extends as far as it does is for historical reasons. Now that multi-system vehicles are easy to build and design, there is really no reason to perpetuate such a system other than the expense of changing it out for something newer (see, also, the 25 Hz PRR NEC system).This sounds peculiar to 600 or 750V DC third rail systems. 12 or 25Kv
AC systems with catenary doubtles have different issues and much lower >>current.
Err, lower current? An Acela trainset draws ?15-20 Megawatts I think.
Even at 12.5 KV, that's a few Amperes.
It's a lot lower than it would be on a (hypothetical in this case) third rail.
In the UK there are suburban services that run 100mph with third rail,
like the line from London Waterloo to Bournemouth and Poole. The
sparks can be pretty impressive, and the cabling sure is.
The original routing of the Eurostar from Paris to London also arrived
at Waterloo with the last part of the high speed trip on third rail.
It now goes to St Pancras under OHLE (do we call it that in ths US?)
the whole way.
Eurostars were significantly limited in power on the 3rd rail, as the supply could only offer something like a third of the power available on 25 kV. The only
reason the UK southern 3rd rail system extends as far as it does is for historical reasons. Now that multi-system vehicles are easy to build and design, there
is really no reason to perpetuate such a system other than the expense of changing it out for something newer (see, also, the 25 Hz PRR NEC system).
On Saturday, December 15, 2018 at 3:19:47 PM UTC-5, hanc...@bbs.cpcn.com wrote:
In the Official Guide of 1954, there were many 'mixed trains' shown
on little branch lines. For whatever reason, they felt it necessary
to mark the train as such.
In further reading, there were a great many mixed trains in 1954.
Almost all the railroads had at least one, sometimes several. Some
of the branches were rather short, like ten miles, but others were
longer. As mentioned, the trains were slow--needing an hour to
travel just ten to twenty miles.
In some cases service was provided in only one direction.
Curiously, the railroads also had listings for many branch lines
that were freight only. There were also numerous tiny carriers
that were freight only.
A few branches did carry passengers, but with the notation
"irregular schedule, consult agent". Must have been a 'fun' trip.
But some hardy railfans liked to rack up rare mileage and actually
sought out and rode those trains.
Have you ever heard of a Parliamentary train, a.k.a. a Parly?
In article <q1e2d0$mnk$1@dont-email.me>,
hounslow3@yahoo.co.uk <hounslow3@yahoo.co.uk> wrote:
Have you ever heard of a Parliamentary train, a.k.a. a Parly?
Yes.
Tesla's motors were fixed speed; set by the line frequency
Sorry for the copious snippage. I think you're rather mixing up the timeli= >ne.
Tesla invented the AC induction motor in the 1880s. DC railway electrifica= >tion became a practical proposition in the 1880s. Early (low frequency) AC=
followed about 20 years later, but mains frequency wasn't viable until the= 1960s. All of these used DC motors. The use of induction motors in railw=
ay traction didn't become viable until the 1980s, a full century after Tesl= >a invented them.
DC motors have their output controlled by voltage. AC motors have their ou= >tput determined by the voltage to an extent and by the difference between t= >he rotational speed and the supply frequency, in an annoyingly non-linear f= >ashion.
Early DC motors had a mix of resistances and series/parallel switching for = >control. Early AC wired the field coils in series with the armature on a D= >C motor and treated the AC as "psuedo" DC. This doesn't work at mains freq= >uency because of inductance effects, but at lower frequency you can get awa= >y with it. This is why the orginal PRR system went with 25 Hz and the De/A= >t/CH system uses 16.7 Hz. Control can be acheived using tap changers. = 20
First time I have an explanation for 25 Hz power that made sense.
In the 1980s power electronics and microprocessor control developed to the = >point where a DC supply could be converted to a 3 phase AC supply where bot= >h the voltage and frequency can be readily controlled, in a package that ca= >n fit on a locomotive or multiple unit. It was this key advance that allow= >ed AC motors to replace DC motors. This is now standard.
Incidentally the same VVVF 3 phase supply is what is used on modern "AC" di= >esel electric locomotives. Because the output of the traction motor is clo= >sely related to the difference between the inverter frequency and the rotat= >ional speed of the motor, it allows really close control over the traction = >motors, allowing things like creep control (making the wheels rotate just a=
tiny bit faster than the road speed dictates) that gives good heavy haul p=
erformance.
On 1/11/2019 04:58, rcp27g@gmail.com wrote:
Early DC motors had a mix of resistances and series/parallel switching
for control.-a Early AC wired the field coils in series with the
armature on a DC motor and treated the AC as "psuedo" DC.-a This
doesn't work at mains frequency because of inductance effects, but at
lower frequency you can get away with it.-a This is why the orginal PRR
system went with 25 Hz and the De/At/CH system uses 16.7 Hz.-a Control
can be acheived using tap changers.
First time I have an explanation for 25 Hz power that made sense.
Robin
In <q1e7rt$2e9s$1@gal.iecc.com> John Levine <johnl@taugh.com> writes:
In article <q1e2d0$mnk$1@dont-email.me>,
hounslow3@yahoo.co.uk <hounslow3@yahoo.co.uk> wrote:
Have you ever heard of a Parliamentary train, a.k.a. a Parly?
Yes.
Have you ever heard of the "white train"?
(yes, there's even a wiki article...)
25 Hz was a common mains frequency in the first half of the C20th. When the modern power grids established themselves, the 60 Hz (or 50 Hz depending on region) became established. If the PRR system had no frequency issues, it is likely they would have converted simply for the sake of standardisation. The reason that they didn't was the rolling stock wasn't able at the time to accept higher frequency. Now, pretty much all of the "needs low frequency" rolling stock is retired, but considering the lifetime of things like the GG1 and similar vintage vehicles, by the time the need for low frequency was passed, the capital for railway investment was less available.I don't think there is anything left that requires 25 Hz; I think
Oh, I agree, but getting up to 100 mph on the way to Bournemouth is
still pretty cool.
I don't think there is anything left that requires 25 Hz; I think
now all equipment can take either 25 or 60 Hz. However, I think
some equipment is still locked into voltage, that is, an 11KV
can't run on 25kV. The newest stuff is more flexible.