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There is no reason this can't be done for modern rail systems. It would greatly improve efficiency and time schedules. But alas, innovation in rail has been ver

There is no reason this can't be done for modern rail systems. It would greatly improve efficiency and time schedules. But alas, innovation in rail has been very incremental (HyperLoop aside), and practically non-existent in the States.

logicallee 8y ago
What's going on with hyperloop these days?
turboProps 8y ago
Uh, electric train cars are all but self propelled, and could carry their own electricity if so desired. Trollies and street cars are individually powered. Slip cars only made sense during the age of steam power, when locomotive power was supplied by huge coal powered engines with furnaces, before internal combustion and deisel made smaller power plants possible. It's interesting, but now we have monorails, magnetic levetation, induction and more, and the concept of coasting to a halt at a precise point pretty much only has utility in amusement parks.
jarfil 8y ago
Rail systems shine when they can concentrate steering an power in more efficient dedicated locomotives, with as many "dumb cars" as possible "automatically" following them (thanks to the rails). But in order to achieve higher granularity and better schedules, cars would have to become more autonomous, which means duplicate steering systems and lower efficiencies... unless there were no efficiency benefits in having a dedicated locomotive, in which case it would make no sense to join cars together in the first place.
- greglindahl 8y ago
  Dedicated locomotive? That's true for things like diesel freight trains, but most high speed electric trains have motors in every car because electric motors scale down just fine.
  - war1025 8y ago
    My understanding is that freight trains use electric motors as well. The diesel engine acts as an electric generator rather than being connected directly to the drivetrain.
    - cup-of-tea 8y ago
      No engines have an internal combustion engine connected directly to the wheels. You can't get anywhere near enough torque. Steam engines have incredible torque. What you're describing is a diesel-electric and is essentially synonymous with saying diesel engine on the railway. There are also electro-diesels which can shut off their diesel engine and take electricity directly from an overhead line or third rail by raising a pantograph or lowering a boot. This used to happen at Faringdon in London (maybe still does).
      - tunareter 8y ago
        You're completely wrong. Most diesel locomotives are in fact diesel electrics. I.e. diesel engine, generator, electric motors. Most of those cannot use external power sources (although a few can, e.g. class 73 in the UK). Certainly in the UK: the most common locomotives such as class 66, 60, 58, 67, 47 - they're all diesel electric. In the US, same story: for passengers the GE Genesis is pretty big, things like SD90MAC and AC6000CW are big for freight.
        cup-of-tea 8y ago
        I think you misread my comment.
      - pmyteh 8y ago
        There are non-trivial numbers of diesel-mechanical (IC to wheels via a gearbox) and diesel-hydraulic (IC to wheels via a fluid coupling) trains out there. The British class 172 Turbostar is an example of the former, most other class 1xx DMUs the latter. Diesel electric transmission does happen on smaller multiple units sometimes, but really shines on larger and faster trains, or on electro-diesels (where you need the electric final drive anyway).
- 7952 8y ago
  Modern passenger trains have motors spread throughout the entire train. It allows them to accelerate better than is possible with a dedicated power car. This is because multiple wheels have more contact with the track. Modern diesel trains have multiple smaller generators spread throughout the train rather than dedicated power cars. Both these approaches give better modularity as the power availabile scales with the length of a train. The efficiency gain in splitting trains is mostly related to reducing the number of drivers needed. It also reduces the demand on track and platforms that may be congested. Both these things could be solved through better automation. Have the train driven by a computer and automate signalling to allow trains to run closer together.
- tialaramex 8y ago
  I'm loving how nobody has called out the fact that this comment pretends trains have "steering systems" and need to "concentrate steering" in locomotives.
  - operationer 8y ago
    https://en.wikipedia.org/wiki/Point_machine https://en.wikipedia.org/wiki/Point_machine It would be kind of tedious to go into great detail. Feels like nerd sniping.
  - teh_klev 8y ago
    I hate to "well actually"...but some loco's do actually have steerable bogies (or trucks). The class 66 is an example of such a loco which permits it to go pretty much anywhere on the UK rail network where the track would previously only allow lighter and less powerful engines. https://www.youtube.com/watch?v=2OGRwD-00b8 https://www.youtube.com/watch?v=2OGRwD-00b8 https://patents.google.com/patent/US20030230213 https://patents.google.com/patent/US20030230213 Not sure if this is what jarfil meant by "steering".
- honestoHeminway 8y ago
  Just dont take the engine and steering along then- the car is propelled and steered out of the station by the rail, brought up to speed, and attached in a gap behind the engine.

logicallee 8y ago

What's going on with hyperloop these days?

turboProps 8y ago

Uh, electric train cars are all but self propelled, and could carry their own electricity if so desired. Trollies and street cars are individually powered. Slip cars only made sense during the age of steam power, when locomotive power was supplied by huge coal powered engines with furnaces, before internal combustion and deisel made smaller power plants possible. It's interesting, but now we have monorails, magnetic levetation, induction and more, and the concept of coasting to a halt at a precise point pretty much only has utility in amusement parks.

jarfil 8y ago

Rail systems shine when they can concentrate steering an power in more efficient dedicated locomotives, with as many "dumb cars" as possible "automatically" following them (thanks to the rails). But in order to achieve higher granularity and better schedules, cars would have to become more autonomous, which means duplicate steering systems and lower efficiencies... unless there were no efficiency benefits in having a dedicated locomotive, in which case it would make no sense to join cars together in the first place.

greglindahl 8y ago
Dedicated locomotive? That's true for things like diesel freight trains, but most high speed electric trains have motors in every car because electric motors scale down just fine.
- war1025 8y ago
  My understanding is that freight trains use electric motors as well. The diesel engine acts as an electric generator rather than being connected directly to the drivetrain.
  - cup-of-tea 8y ago
    No engines have an internal combustion engine connected directly to the wheels. You can't get anywhere near enough torque. Steam engines have incredible torque. What you're describing is a diesel-electric and is essentially synonymous with saying diesel engine on the railway. There are also electro-diesels which can shut off their diesel engine and take electricity directly from an overhead line or third rail by raising a pantograph or lowering a boot. This used to happen at Faringdon in London (maybe still does).
    - tunareter 8y ago
      You're completely wrong. Most diesel locomotives are in fact diesel electrics. I.e. diesel engine, generator, electric motors. Most of those cannot use external power sources (although a few can, e.g. class 73 in the UK). Certainly in the UK: the most common locomotives such as class 66, 60, 58, 67, 47 - they're all diesel electric. In the US, same story: for passengers the GE Genesis is pretty big, things like SD90MAC and AC6000CW are big for freight.
      - cup-of-tea 8y ago
        I think you misread my comment.
    - pmyteh 8y ago
      There are non-trivial numbers of diesel-mechanical (IC to wheels via a gearbox) and diesel-hydraulic (IC to wheels via a fluid coupling) trains out there. The British class 172 Turbostar is an example of the former, most other class 1xx DMUs the latter. Diesel electric transmission does happen on smaller multiple units sometimes, but really shines on larger and faster trains, or on electro-diesels (where you need the electric final drive anyway).
7952 8y ago
Modern passenger trains have motors spread throughout the entire train. It allows them to accelerate better than is possible with a dedicated power car. This is because multiple wheels have more contact with the track. Modern diesel trains have multiple smaller generators spread throughout the train rather than dedicated power cars. Both these approaches give better modularity as the power availabile scales with the length of a train. The efficiency gain in splitting trains is mostly related to reducing the number of drivers needed. It also reduces the demand on track and platforms that may be congested. Both these things could be solved through better automation. Have the train driven by a computer and automate signalling to allow trains to run closer together.
tialaramex 8y ago
I'm loving how nobody has called out the fact that this comment pretends trains have "steering systems" and need to "concentrate steering" in locomotives.
- operationer 8y ago
  https://en.wikipedia.org/wiki/Point_machine https://en.wikipedia.org/wiki/Point_machine It would be kind of tedious to go into great detail. Feels like nerd sniping.
- teh_klev 8y ago
  I hate to "well actually"...but some loco's do actually have steerable bogies (or trucks). The class 66 is an example of such a loco which permits it to go pretty much anywhere on the UK rail network where the track would previously only allow lighter and less powerful engines. https://www.youtube.com/watch?v=2OGRwD-00b8 https://www.youtube.com/watch?v=2OGRwD-00b8 https://patents.google.com/patent/US20030230213 https://patents.google.com/patent/US20030230213 Not sure if this is what jarfil meant by "steering".
honestoHeminway 8y ago
Just dont take the engine and steering along then- the car is propelled and steered out of the station by the rail, brought up to speed, and attached in a gap behind the engine.