UK Rail and Trains

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Mex

The dream of the first hydrogen rail network has died a quick death (qz.com)

submitted 1 year ago by Mex to c/rail

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Lets keep this in the bag for when the UK government thinks this is a good idea here.

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[–] Emperor 4 points 1 year ago (2 children)

I had to wonder about the point of this - railways are set up to use electricity, it would seem the simplest thing is just to go all in on that.

I do wonder about the railways utilising the large surface areas they have to generate electricity. Banging solar panels on sheds and stations is a no-brainer but, with better solar panel technology (printable, flexible, more robust, etc) could you not lay miles of them alongside (or even between?) the tracks? They could end up generating all the electricity they needed.

[–] Mex 2 points 1 year ago

you wouldn't want anything on the track bed because it would hinder maintenance and observability too much. But no so much "rail" land that is basically empty elsewhere.

[–] Patch 2 points 1 year ago (1 children)

My thoughts exactly. What on earth is the point of hydrogen trains when electric trains have been a thing for about 150 years? I guess it might be marginally cheaper to switch diesel to hydrogen vs installing overhead lines or third rails, but considering the cost of setting up hydrogen infrastructure (not to mention developing the rolling stock) I doubt it's vastly cheaper.

Overhead lines supplemented with chemical batteries for short stretches where it's impractical seems like the solution in almost all cases.

[–] mackwinston 3 points 1 year ago* (last edited 1 year ago)

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.