Some time in this century our crude oil will be mostly tapped out and most uses of what remains will be very limited.
( This was projected by end of 20th century but new technology and shale deposits have thrown us a life line.)
I state following because I am totally convinced that our RofF will have diesel trains carrying out chromite ore out of the Ring.
So what is likely to happen with our diesel powered trains?

One answer could be electrically powered engines, but can you imagine adding electrical towers and powering cables to existing railway lines? Electrical power for densily populated regions transporting people, with many stops for pick up and drop off, is the answer presently and that is not likely to change.

But for trains for long distances, hydrogen power may be just the right answer instead of adding elecrical cabling to existing lines. Hydrogen fuel is just electrical power packaged physically. Cost difference will determine which method will be used where.

Good to have options.