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Railroad wheels and energy generation

  1. Aug 19, 2016 #1
    How much energy generation potential would one rolling wheel on a train produce if it was hooked up to a generator if the train is rolling with continual momentum at various speeds. What is the reasonable optimum velocity of the train to maximize energy generation?

    How would you figure this out or set up an experiment?
    Is it similar to hydroelectric turbine?

    Thank You,
    Rick Thomas Simmons
    Last edited by a moderator: Aug 19, 2016
  2. jcsd
  3. Aug 19, 2016 #2


    Staff: Mentor

    Typically it would produce about 1/3 of the additional energy that would be spent in keeping the train rolling against the extra load. So a net loss of 2/3.

    The optimum would be zero. No energy would be produced, but the losses would be avoided also. Since the losses exceed the gains, the best you can do is stop.
  4. Aug 20, 2016 #3


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    Most Energy Harvesting is a waste of time but the owners of a length of rail track could steal energy from passing trains (fuelled by a different company). But they would have do do this by stealth!
  5. Aug 20, 2016 #4


    Staff: Mentor

    Railroad locomotives have been doing that since 1936. They call it regenerative braking (or dynamic braking). It is especially used when going down hill. See https://en.wikipedia.org/wiki/Regenerative_brake

    However, if you think that it can be used to get free energy while the train is moving at constant velocity on level ground, that is called perpetual motion, and that topic is forbidden on PF.
  6. Sep 3, 2016 #5


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    Staff: Mentor

    There are long steep inclines where a loaded electric train needing to ascend the incline has been required to do so while a train on a parallel line is descending, so that the regenerated power pushed into the overhead conductor by the descending loco can aid the ascending loco. When a descending train is not available, a diesel loco can be brought in to provide the extra grunt.
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