Hydrogen instead of diesel – major rail project in Hesse


No less than the “world’s largest fleet of hydrogen trains” is to roll over the rails of the Rhine-Main area from next year. The necessary hydrogen comes from the Frankfurt-Höchst industrial park, where the gas is produced in large quantities as a waste product from chemical processes. The fleet of 27 trains will be serviced from December 2022 at the DB Regio plant in the nearby Griesheim district, as Deutsche Bahn, the Rhein-Main-Verkehrsverbund (RMV) and Alstom announced on Friday. Whoever drives the trains will be advertised across Europe in the next few weeks, as RMV Managing Director Knut Ringat announced.

“We are the largest manufacturer of diesel trains in Germany and we asked ourselves what will come after the diesel”, says Alstom manager Jörg Nikutta. The answer for the non-electrified sub-network with four routes in the Taunus and west of Frankfurt was ultimately fuel cells. Instead of diesel, Alstom has installed them, including hydrogen tanks and buffer batteries, in its local train, which has been tried and tested hundreds of times. With a range of around 1000 kilometers and a high level of reliability even in difficult weather, the iLINT trains should not be inferior to diesel in decisive criteria, and as little change as possible should also be made for the train drivers.

The trains, which have also been tested in northern Germany and Baden-Württemberg, were bought by the RMV subsidiary fahma for around half a billion euros in order to simplify the otherwise overly complicated tendering processes with the new technology. Together with Infraserv Höchst, Alstom ensures the energy supply and has now entrusted DB Regio with the maintenance of the trains. The railway subsidiary will also certainly participate in the tender for the train operation, as announced by board member Oliver Teerhag.

With an expected service life of 25 years, one had to look around for alternative drives in order to achieve the climate targets, says RMV man Ringat, describing the initial situation. Considered over the entire period, the testing of the so far little used fuel cell technology is worthwhile. Ultimately, the availability of hydrogen in the industrial park and the lack of electrification on the Taunus routes were decisive.

Because the trains do not need overhead lines. In the fuel cells mounted on the train roof, hydrogen reacts cleanly with oxygen from the ambient air. The result is heat, electricity for the engines and water vapor as a waste product. From climate-damaging substances such as CO2, Nitrogen oxides or fine dust is not a trace in this process. However, hydrogen, the most common chemical element in the universe, must first be removed from its natural compounds using a great deal of energy.

In the Frankfurt-Höchst industrial park, this has been happening in the production of organic raw materials in chlorine chemistry for more than 100 years. Experience with the volatile gas, which is explosive under certain conditions, is therefore abundant. A lot of fossil energy is initially used for chlor-alkali electrolysis, which is why the “gray” hydrogen obtained in this way cannot yet be considered climate-neutral.

So far, the gas in Höchst has been used to produce agricultural fertilizers or has simply been burned. A train filling station is now being built on the rails. A large electrolysis plant is being built as a backup, which can also use purchased green electricity to produce as much hydrogen as the Taunus trains need. With this device, water can be split into oxygen and hydrogen.

In the DB Regio repair shop in Griesheim, boss Ingo Albrecht and his 220-strong team are looking forward to the new vehicle. 1.2 million euros will initially be invested, including in a modern roof ventilation system in the event that hydrogen should ever escape.

There will be no additional jobs for the time being, explains DB board member Teerhag, because initially the work in the workshops will be reorganized and distributed. Many components of the new trains are also identical to older models. It is also clear to the mechatronic engineers that you cannot hold onto the diesel forever. Because by 2040, Deutsche Bahn wants to have replaced all diesel drives with climate-friendly alternatives.