Yet EPA officials said the rule will not mandate the adoption of a particular zero-emission technology. Rather, it will require manufacturers to reduce emissions by choosing from several cleaner technologies, including electric trucks, hybrid trucks and hydrogen fuel-cell vehicles.
For comparison, the New York Times coverage
Considering locomotives are diesel-electric hybrids, it would make sense to move trucks to a similar technology. Replace the weight of a huge engine and transmission with a smaller generator and battery pack.
I don’t believe locomotives have batteries - the generator output directly feeds the traction motors. The locomotive power curve is basically - a shitload of power near zero speed to get the train moving, or a shitload of power at cruising speed to keep it moving; not so much stop and start and various speeds like most road vehicles. So a battery energy reserve doesn’t do much.
And locomotive engines are some huge, heavy mofos.