6 ms·

Of course modern trains have electric motors on each car, and engines are just giant diesel generators making the electricity...

cbr 12y ago
[citation needed] I'm not seeing anything about this; everything online says standard trains are still an active locomotive and passive cars.
- ChuckMcM 12y ago
  http://en.wikipedia.org/wiki/Multiple-unit_train_control http://en.wikipedia.org/wiki/Multiple-unit_train_control covers the gist of it. One of the challenges of long trains is that you can't easily start them on a curve. As the front of the train is pulled it wants to 'straighten out' and that would pull mid-train cars off the track, Such trains if they don't use MU put locomotives both in the back and the front (and some times mid-train). The advantage of standardized MU is that your engine is simply a control center (especially if you're using power from overhead catenary wires) and any train of any length can "work" because the traction motors in every car are sufficient to push that car with some flexibility (some can push up to two additional 'dead load' cars.) But as others have pointed out, in the US the tracks are primarily straight, the existing traction motors in diesels system works well enough, and there is little incentive to change. That said, one of the options on the table for electrified CalTrain is MU equipped cars so that train sizes can be varied depending on commute load.
  - cbr 12y ago
    MU allows you to have multiple locomotives controlled together, but individual train cars still generally don't have traction motors. There are specialized traincars that have motors but not generators [1] but I don't think these were what foobarian was referring to. [1] http://en.wikipedia.org/wiki/Slug_(railroad) http://en.wikipedia.org/wiki/Slug_(railroad)
  - ubernostrum 12y ago
    The exact claim being responded to was "modern trains have electric motors on each car".
comrade1 12y ago
The trains in the u.s. are still pretty primitive. Do a google image search on amtrak for some cringeworthy pics. Where I live in Europe the only trains where the engine pulls are freight trains. All passenger trains except some cog-wheel trains in the mountains have diesel electric generators and individual motors on each wheel.
- ams6110 12y ago
  In the USA, freight is the vast majority of rail traffic, excepting a few highly populated corridors in the northeast and commuter lines in a handful of other urban areas.
- tanzam75 12y ago
  While Switzerland has opted to go all-EMU for its passenger trains, that's not true of every country. For example, the only powered axles on the French TGV are at the front and rear of the train. All the axles in-between are unpowered. The TGV isn't exactly a primitive train. The TGV was the basis of the Spanish AVE and the Korean KTX. The KTX also uses additional powered axles on the first and last cars, but it still has a lot more unpowered axles than powered ones. As for Amtrak, the Acela isn't a primitive train. It's a mashup of the French TGV and the Canadian LRC. And yes, it has unpowered axles in the middle. Its main problems are its excessive weight (forced by FRA regulations), and the totally inadequate investment in the track over the last 80 years. The basic design isn't that bad.
  - iSnow 12y ago
    >The TGV was the basis of the Spanish AVE Well, the AVE 103 is based on the Velaro platform which most certainly has powered axles on every car, as you would expect from a German train. The same goes for the Russian Sapsan, the Chinese CRH3 and the German ICE3
    - tanzam75 12y ago
      The AVE 103 may be based on the Velaro, but the AVE 100, 102, and 112 are based on the TGV, which has non-powered passenger cars. The point is that non-powered passenger cars do not automatically indicate a "primitive" rail system, as the previous commenter seemed to think. Some countries have made one choice, other countries have made the other choice, and some countries even use both technologies simultaneously. And that's just high-speed trainsets. It's quite common to find non-powered passenger cars on conventional trains as well.
nhaehnle 12y ago
This is true for many modern high-speed trains (though those tend to not be diesel trains...), but those are only a small fraction of all trains. Upgrading all existing freight cars with dedicated motors would be a crazy effort. Of course you could argue that freight trains aren't modern, which would make your comment correct in the worst sort of way ;-)
dredmorbius 12y ago
This may be the case on electric passenger rail, and generally is the case for high speed passenger rail, where each carriage, and sometimes each wheelset, is powered. However even for electric freights, you'll typically have a small number of traction wheels on the actual traction units.

cbr 12y ago

[citation needed] I'm not seeing anything about this; everything online says standard trains are still an active locomotive and passive cars.

ChuckMcM 12y ago
http://en.wikipedia.org/wiki/Multiple-unit_train_control http://en.wikipedia.org/wiki/Multiple-unit_train_control covers the gist of it. One of the challenges of long trains is that you can't easily start them on a curve. As the front of the train is pulled it wants to 'straighten out' and that would pull mid-train cars off the track, Such trains if they don't use MU put locomotives both in the back and the front (and some times mid-train). The advantage of standardized MU is that your engine is simply a control center (especially if you're using power from overhead catenary wires) and any train of any length can "work" because the traction motors in every car are sufficient to push that car with some flexibility (some can push up to two additional 'dead load' cars.) But as others have pointed out, in the US the tracks are primarily straight, the existing traction motors in diesels system works well enough, and there is little incentive to change. That said, one of the options on the table for electrified CalTrain is MU equipped cars so that train sizes can be varied depending on commute load.
- cbr 12y ago
  MU allows you to have multiple locomotives controlled together, but individual train cars still generally don't have traction motors. There are specialized traincars that have motors but not generators [1] but I don't think these were what foobarian was referring to. [1] http://en.wikipedia.org/wiki/Slug_(railroad) http://en.wikipedia.org/wiki/Slug_(railroad)
- ubernostrum 12y ago
  The exact claim being responded to was "modern trains have electric motors on each car".

comrade1 12y ago

The trains in the u.s. are still pretty primitive. Do a google image search on amtrak for some cringeworthy pics. Where I live in Europe the only trains where the engine pulls are freight trains. All passenger trains except some cog-wheel trains in the mountains have diesel electric generators and individual motors on each wheel.

ams6110 12y ago
In the USA, freight is the vast majority of rail traffic, excepting a few highly populated corridors in the northeast and commuter lines in a handful of other urban areas.
tanzam75 12y ago
While Switzerland has opted to go all-EMU for its passenger trains, that's not true of every country. For example, the only powered axles on the French TGV are at the front and rear of the train. All the axles in-between are unpowered. The TGV isn't exactly a primitive train. The TGV was the basis of the Spanish AVE and the Korean KTX. The KTX also uses additional powered axles on the first and last cars, but it still has a lot more unpowered axles than powered ones. As for Amtrak, the Acela isn't a primitive train. It's a mashup of the French TGV and the Canadian LRC. And yes, it has unpowered axles in the middle. Its main problems are its excessive weight (forced by FRA regulations), and the totally inadequate investment in the track over the last 80 years. The basic design isn't that bad.
- iSnow 12y ago
  >The TGV was the basis of the Spanish AVE Well, the AVE 103 is based on the Velaro platform which most certainly has powered axles on every car, as you would expect from a German train. The same goes for the Russian Sapsan, the Chinese CRH3 and the German ICE3
  - tanzam75 12y ago
    The AVE 103 may be based on the Velaro, but the AVE 100, 102, and 112 are based on the TGV, which has non-powered passenger cars. The point is that non-powered passenger cars do not automatically indicate a "primitive" rail system, as the previous commenter seemed to think. Some countries have made one choice, other countries have made the other choice, and some countries even use both technologies simultaneously. And that's just high-speed trainsets. It's quite common to find non-powered passenger cars on conventional trains as well.

nhaehnle 12y ago

This is true for many modern high-speed trains (though those tend to not be diesel trains...), but those are only a small fraction of all trains. Upgrading all existing freight cars with dedicated motors would be a crazy effort. Of course you could argue that freight trains aren't modern, which would make your comment correct in the worst sort of way ;-)

dredmorbius 12y ago

This may be the case on electric passenger rail, and generally is the case for high speed passenger rail, where each carriage, and sometimes each wheelset, is powered. However even for electric freights, you'll typically have a small number of traction wheels on the actual traction units.