Rail might correctly consider itself the greenest transport mode, but there is nevertheless plenty railways can do to decarbonise – not least by doing away with diesel as the primary fuel to power trains on non-electrified lines.
The question then comes: how best to do that?
Anyone who follows the discussion about the future of railways ends up hearing about hydrogen as the most hyped alternative power source. Alstom has been making waves with its iLint train – and that has been running between Cuxhaven and Buxtehude in Northern Germany since 2018. 16 hydrogen trains will serve that line, and a further 27 will run on routes around Frankfurt starting in December 2022. At some point in the future 7 further hydrogen trains will run on a line to the north of Berlin. 50 trains in total.
But there are a couple of major problems with hydrogen as a power source source for trains. The most notable is the difficulty obtaining adequate supplies of green hydrogen. Michael Liebreich has done a lot of work about this with his hydrogen ladders, and tried to break down what uses are appropriate for hydrogen in transport (see his hydrogen ladders here). The second is that while fuel cells might be lighter than batteries, the power efficiency of a hydrogen train is lower than a battery train.
Motivated by that, and using my Brexit Diagrams as a basis for how to explain complex problems, I tried to map out how decisions about the decarbonisation of rail should be made. These are the diagrams from the train and from the network perspective:
To read further, & to see the other decision diagram, click on this link below: