sustainability transport

Britain to get its first hydrogen trains

In 2017 the French rail multinational Alstom unveiled its new zero carbon train, powered by hydrogen fuel cells. The company signed deals to supply them to the German rail network earlier this year, and last week we learned that the technology will be coming to Britain too.

It won’t be exactly the same train. To speed things up, Alstom will be retrofitting an existing fleet of electric trains to run on the fuel cells. No word yet on where they will run or when they’ll be ready, as far as I know, though do let me know if you’ve heard.

This is good news, first because hydrogen trains can be zero carbon – depending on how you produce the hydrogen of course. They are quiet and non-polluting, and if they can replace diesel trains that would mark a considerable improvement. The second reason is that the government recently cancelled three rail electrification schemes because they cost too much. With all three schemes long promised and endlessly delayed, that decision provoked an angry reaction. But hydrogen trains could potentially decarbonise the railways for less money and far less disruption than fitting overhead cables on large parts of the network. And if older trains can be succesfully retrofitted, a transition to hydrogen could be cheaper and faster than we thought. It’s definitely a project to keep an eye on.

Whenever they arrive, those hydrogen trains will build on a long term trend in the right direction on Britain’s railways. More electric trains are running, and more people are using them. Together that is bringing down the CO2 per passenger kilometre, with the carbon footprint of train travel falling by 25% over the last decade or so.


  1. A pilot that might make sense would be the line from Thurso to Inverness given the investment in hydrogen technology taking place on Orkney, where there is a glut of wind/tidal power and because of the commitment of the Scottish Energy Strategy to low carbon transport.

  2. How the hydrogen is produced is key. The easiest source is probably as by-product from the petrochemical industry, which makes it anyway e.g.Teeside. But that will not aid decarbonisation.

  3. Good points, and using surplus Scottish renewable energy to make hydrogen could well be more efficient than running it across the country to where it’s needed.

  4. Hydrogen is a terrible transport fuel. It has a critical temperature of minus 240 degrees C, which means that it has to be compressed (which consumes energy), and carried in heavy cylinders to withstand the pressure. There is a limit to how much it can be compressed, which results in a low energy density. The range of such trains would be limited. The re-conversion of hydrogen back to electricity in fuel cells is not particularly good. One can envisage such a train running successfully on a short branch line with level track, such as St Ives in Cornwall. The overall energy consumption, including embodied energy over the cycle also has to be considered, from the mining of the raw materials to the disposal of the end-of-life waste. Apart from such niche applications, this technology promises little.

    Important ways of reducing the energy footprint of railways would be slower running, prolonging the life of railway vehicles by refurbishment rather than replacement and a return to steel construction for railway vehicles instead of the now fashionable aluminium; the saving of weight is trivial and aluminium bodyshells incorporate a horrendous amount of embodied energy.

    As regards point-of-use pollution, the most effective measure would be to burn oil fuel in a steam locomotive rather than in an internal combustion engine. This avoids production of NOx and particulates, at marginally lower efficiency; steam locomotives also have the advantage of a service life about double that of the internal combustion equivalents, with corresponding reductions in embodied energy. Fifty years after they were taken out of service, the most powerful prime-mover locomotive in Britain are still steam locomotives!

    The train in the picture does nothing that a 1930s branch line auto-train did not do equally well with a few shovelfuls of coal an hour; it is hardly going to save the planet. I am not suggesting that it does any harm to experiment with a old train which would otherwise go for scrap but this is technological overkill. There is an article on the subject by Roger Ford in the May edition of Modern Railways. The hydrogen powered train is a good example of how it is easy to miss the bigger picture.

  5. Alstom wouldn’t be able to market this unless it was a viable technology, and it’s performance is equivalent to the trains it would be replacing. They have a range of 600-800km, and a speed of 140km an hour, so they’re not limited to short local routes. I take your point on steam engines being more efficient than combustion engines, but if the plan is to shift away from fossil fuels, fuel oil only gets us so far.

    On materials and longevity, absolutely. I was interested to see a news story this year about a mothballed fleet of late 80s trains that are going to be refurbished and brought back into service between London and Portsmouth. Apparently they’re more reliable and passengers preferred them to the new ones. Knacked and slow trains will only encourage people back into their cars, but where stock can be modernised and kept in service, that will avoid the embodied carbon as well as keeping prices lower.

    1. Ford describes the Alstom i-Lint as a “political train”. It cannot leave much change out of £4 million for a couple of carriages. It does nothing that a re-engineered old train could not do better at a quarter of the price, or less. Nice work for Alstom, which has no incentive to offer lower cost solutions when it can sell expensive ones to ill-informed politicians.

      The high cost of trains is an important reason why there is a general rule which has applied, with few exceptions, since at least the mid-1960s: the newer the trains, the more cramped, uncomfortable and unpleasant they have been, and the more overcrowded are the routes on which they run. The reason is simple: the overpriced train has to earn its very expensive keep, which can only be done by cramming people in and providing little or no space for their luggage, thereby turning rail travel into a distress purchase. The high cost of new trains is the principal reason for the chronic shortage of rolling stock, which makes inefficient use of the infrastructure by filling the system up with short trains.

      As regards energy use, hydrogen is, as Ford explains, an inefficient vector for transmitting electrical power from a generator to the wheels. It is probably more cost-effective to use unwanted electricity to generate hydrogen and just pump it into the gas supply grid, thereby decarbonising some other part of the economy; after all, coal gas contained a high proportion of hydrogen, so this is nothing new.

      That said, putting a fuel cell under the floor of a retired London Underground train and running it along the shore at sea level between St Erth and St Ives is not a bad way of testing the technology. However, to provide a benchmark for the trials, a 1930s Great Western autotrain should be borrowed and used for comparison on the same service.

      More generally, a lot of decarbonised energy is not, when the carbon-derived energy used to dig the raw materials out of the ground and build the structures is taken into consideration.

  6. But the autotrain would not be low carbon, and if paired with renewable energy a retrofitted hydrogen fuel cell train could be. We could bring back steam trains and run them on wood, but then we’d have no trees left and be no better off. It’s all about that carbon bottom line.

    One of the good things about this initiative is that Alstom are retroffiting a fleet of Class 321 trains, so we’re not getting that overpriced iLint and its embedded carbon.

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