It's not green since most of it is produced from fossil fuels.

Dear Faust, it's them again. Them who say "electricity is not green since most of it is produced from fossil fuels"

It's also disgustingly expensive even compared to fossil fuels

Hydrogen is mean of storage, not source

it takes something like 3-4x the energy to produce, store, transport, and convert back to energy as just charging a battery.

Ehhh. 60% efficiency means 1.6x the energy to produce. And battaries are transported too.

In the case of trains it seems more sensible to manufacture biodiesel or synthetic fuels than this. It's certainly safer to transport and store. Perhaps existing trains can be converted relatively easily. Or electrify the train line or stretches of it.

Electrify? Yes! Everything else? Meh.

Or even put solar on carriages to reduce fuel consumption during daylight operations.

Small area, create drag, may be even energy-negative. Worse idea than hydrogen storage.