Are there any energy-recuperation systems for subways/metro/underground using the brakes?

Question

I heared such a system was still in the development fase in Japan (for above-ground trains). Recently I read that there already is such a system for years in the metro of Brussels. Could this be true?

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using the friction energy of the brakes to generate power for the train

Answer 1

You bet - and this has been done for nearly 100 years.

http://books.google.com/books?q=locomoti...

The technology is very straightforward, railway traction motors can be reconfigured as generators. It's called regenerative or dynamic braking.  The difference is: regen puts power back for use by other trains, dynamics just waste the energy in giant resistor banks (kinda like an electric wall heater, but gigantic.)

BART trains do both.  They regenerate the power to the third rail if there's another train around which needs the power.  If not, they burn it up in resistors.  BART does not have the ability to regenerate back into the national power grid - I'm not aware of any systems that do - yet.

If you try to regenerate and you're the only train in the system, you end up making the line voltage too high.  The Illinois Railway Museum has an old South Shore "Little Joe" (as in Joe Stalin, leader of Russia at the time, who it was almost sold to) which I believe has regen.  Legend has it IRM tried out the regen, and nearly burned down their wire!

Virtually all diesel locomotives have dynamics.  A diesel can actually dynamic brake harder than it can push.  Nowadays in mountain districts they send helper engines not to help push up the hill, but to help dynamic brake down the hill.

Answer 2

Well, the simple answer is yes and no.

nothing that uses the friction or axle brakes that I know of but the most efficient way to brake a train is using "dynamic or regenerative" braking where the axle mounted electric motors are reconfigured to become generators causing a very effective retarding force.

I worked on a railroad years and years ago that did in fact have that very same system, it was all electric, as trains went into braking mode the traction motors became generators, electricity generated was put back into the lines and made available for other trains.  There were substations every 30 miles or so to regulate the amount of power available for trains, adding to or subtracting from as needed to keep the line voltage stable.

In effect, one train going downhill was actually "pulling" another train coming up that same hill.

System was installed in the early 1900's and worked so well that they took it out so the oil companies could sell millions and millions more gallons of fuel.

Answer 3

This technology has been around for a while and is becoming more efficient all the time. Its not friction energy, that would be a redundant step. The "brakes" are generator/motors and when you apply them the generators are driven by the wheels like a pulley on a continuous never ending belt of metal. I think the train in japan you are talking about doesn't even have wheels and simply floats on a magnetic field generated by the rail. I wish i had a link on that one it is extremely efficient.

Answer 4

I believe Virgin Trains "Penodlino" long distance trains in the UK do have Regenerative Braking that sends power to the National Grid. I think its a fantastic way to save energy, as it means very little effort. A much better idea then those big ugly wind turbines!