At InnoTrans 2026 in Berlin, the Swiss train manufacturer Stadler unveiled the world’s first hydrogen-powered train developed specifically for narrow-gauge railways.
In collaboration with 3 Italian rail operators, Stadler is building 21 trains for Sardinia, Calabria, and Sicily. 10 of these hydrogen-powered trains will save more than 2,100 tonnes of CO2 per year compared to diesel trains, equivalent to approximately 450 trips around the world by car.
Narrow-gauge track in Italy is 950 mm wide
At its Swiss factory in Bussnang, Stadler – one of Europe’s major players in the field of rolling stock, alongside Alstom and Siemens Mobility – is building 10 trains for ARST in Sardinia, 9 for Ferrovie della Calabria, and 2 for Ferrovia Circumetnea in Sicily.
It is a modular platform that is adapted to each region. This includes coastal routes in Sardinia, mountain tunnels in Calabria, and the steep slopes around Mount Etna. Italy’s narrow-gauge track is 950 mm wide, compared to 1,435 mm for standard-gauge track.
In Sardinia, starting in 2028, trains will operate on the Alghero Airport-Mamuntanas, Sassari-Alghero, and Sassari-Sorso routes. Partially funded by the EU, the projects are part of an Italian initiative to make regional rail more sustainable.
Compact design and lightweight materials
The main problem with narrow-gauge railways is weight. Italian narrow-gauge lines require vehicles with a low axle load. As a result, you can’t simply adapt an existing hydrogen train. Stadler therefore opted for a slim, compact design and lightweight materials.
These two-car trains feature a power pack car that houses the fuel cells and hydrogen tanks. These work in conjunction with traction batteries, which are charged using the energy generated during hydrogen combustion. This allows the trains to operate emission-free even on non-electrified routes. The required hydrogen must be produced using solar energy, so the 3 transit operators are currently building their own facilities.
Stadler says they are quieter than diesel trains and feature large panoramic windows and a low entry.
Test case
Germany is a pioneer in hydrogen trains. The Alstom Coradia iLint has been operating in Lower Saxony (EVB) since 2018 and later in the Taunus region (RMV). It was the first hydrogen train in passenger service.
The Siemens Mireao Plus H operates in Bavaria and Berlin-Brandenburg, among other places. The Stadler FLIRT H2, by contrast, operates in California. In 2024, that train set a record: 2,803 km without refueling or recharging.
Pilot projects had existed before, such as an Austrian project (HyTrain) for a hydrogen train on the Zillertalbahn narrow-gauge line, but this is the first hydrogen train specifically developed for narrow-gauge rail and built in series production.
In Lower Saxony, however, hydrogen supply proved problematic. Because of those disappointing experiences and high hydrogen prices, the system could switch back to electric trains starting in 2029.
That’s what makes the Sardinian project interesting: producing hydrogen locally using solar energy directly addresses the supply and cost issues that Germany ran into. Whether it works remains to be seen once the trains begin operating in 2028.
