As a Chemical Engineer, I am horrified by the idea of using hydrogen as a fuel in passenger carrying vehicles. It is a very small molecule capable of diffusing through flexible hoses. It can diffuse into metals making them brittle and subject to cracking and fracture particularly in a mobile vibrating environment where fatigue is an issue, making connecting networks risky. It has to be stored at high pressures, 350 - 700 bar - multiply by 15 to give psi! Its energy density is low so it needs typically four times the storage volume of diesel. The steel pressure vessels must be circular not rectangular and have thick heavy walls, up to 10% of diameter. It has wide flammability limits in air that other fuels do not have, making leaks likely to catch fire, with high flame speeds as opposed to hydrocarbons. Even if the above could be overcome, it must be a costly derived and manufactured fuel.
The words Abergele, Hawes Jn, Ais Gill, Quintinshill and Charfield spring to mind.
Don't even stand on the same platform, let alone travel on one.
WAO