Uh, that is just part of the guy on the left's quad there, right? I'm just seeing things, this doesn't need a NSFW tag right? It wouldn't the first time a candid sports picture captured an accidental reveal.

Was going to say it tells you to walk to the front or back of the train, since those cars are generally less full, but I saw someone else had already made the same point further down.

Environmentalists are not the ones pushing for hydrogen. Look at who actually is pushing it and funding lobbying groups behind it - it's the natgas/fossil fuels industries, desperately trying to push something they can produce and control into these sectors. Same as with heating, other areas of transportation, and storage.

Yes. The round-trip conversion to first produce then use hydrogen is significantly less efficient than directly using the electricity or fossil fuels themselves. Problem is batteries aren't energy dense enough for long-range flight and fossils are dirty. However, hydrogen - unless frozen and compressed - also has terrible energy density and requires highly specialized storage and handling. The better solution IMO is not stopping at hydrogen but going to fully synthetic fossil fuels, but either way will require massive surpluses of green power that don't exist yet. Right now 99% of hydrogen comes from natgas.

Fully synthetic fossil fuels using green energy to manufacture. Still massively energy intensive, would need the same hydrogen as a feedstock, but vastly safer, more stable, uses existing infrastructure, and would be carbon neutral.