Hydrogen is pretty much a non-starter for all transport. It’s usually an excuse to do nothing on the lines of “But we’ll have hydrogen powered X soon, so therefore we don’t have to do proven technology Y”

The problems of hydrogen are:

• Tragically poor energy density by volume. Hydrogen cannot be liquified at any reasonable temperature (its critical temperature is on the order of 30K, or about -243 C) so it has to be compressed to immense pressures to get any kind of energy density at all.
• H2 is the smallest molecule, it leaks through most pressure vessels, making them brittle in the process, the last thing you want to have in a 3500+ PSI container. Because it’s constantly leaking, you’re constantly losing fuel.
• It is only economical to make it from fossil fuels and this will be the case for some time to come. You might as well just use the fossil fuels directly and avoid the difficulty of handling hydrogen and the associated losses making it.

Overhead wires are proven and efficient technologies. You can have more powerful locomotives running off overhead wires than anything self powered (the most powerful diesel freight locos in the UK are around ~3300 hp, and even an elderly class 87 electric loco is around ~5500 hp). For railways if it’s fast, frequent or freight, overhead electrification is best.