How would this charge? Would you just swap out locomotives (battery cars?) periodically?
We have electric trains in city via overhead wires. I assume this becomes impractical at the freigh rail scales.
Diesel locomotives have always been diesel generators mated to electric motors (too much torque for a transmission), so a battery pack is a natural progression for the powertrain. Zero emissions requires either green energy produced hydrogen or ammonia for combustion.
I always wondered if it would make sense to have a battery "tender" that could accept this current from a relatively stock diesel engine... so you replace, say, four straight diesels with three and one battery tender.