On Aug 12, 11:14*am, Roland Perry wrote:
You might be able to apply some of the engine-improvement technology to
DMUs, but can electric motors be made any more efficient?

Yes:
1) three-phase induction motors instead of synchronous DC motors
2) regenerative braking

These have been done. This is why overall energy consumption for new
electric trains isn't substantially higher than for older electric
trains, despite their much higher peak power ratings.

--
John Band
john at johnband dot org
www.johnband.org