No problemo
.
I wonder how much energy it takes to shoot a 25 ton aircraft off a carrier deck in less than 2 seconds?
Current Diesel electrics use a giant stove on top of the engine to convert brake energy into waste heat, because they couldn't possible put it into any battery that quickly.
Carry an accumulator car behind the engine to store that same energy.
Now you can pulse and glide a train!
Using that same accumulator-drive system.
They use electric motors because no transmission would hold up, so they have the same issues with mileage as a Chevy volt.
regards
Mech