Swiss locomotive manufacturer Stadler and Sardinian regional operator ARST (Azienda Regionale Sarda Trasporti) have unveiled the world's first hydrogen-powered train built for narrow-gauge track. That's a genuine first because the narrower track imposes axle-load limits so tight that no existing hydrogen train could fit, and an entirely new vehicle had to be designed from scratch.
Sardinia, Calabria, and Sicily inherited their rail networks from the 1800s, complete with a track gauge of 950 mm (37.4 in), significantly narrower than Europe's standard 1,435 mm (56.5 in). That gap creates tight axle-load limits that make it impossible to simply adapt any existing hydrogen train. Stadler had to engineer a new lightweight aluminum body profile from the ground up to fit.
The propulsion concept will be familiar to anyone who's followed hydrogen rail in Europe. Fuel cells convert compressed hydrogen into electricity, which charges traction batteries that drive the train. But the packaging is different here. Rather than distributing hardware across rooftops, as Alstom and Siemens do on their standard-gauge models, Stadler concentrated the entire system into a dedicated central car called the Power Pack, freeing up the passenger cars for air conditioning, panoramic windows, and low-floor boarding for reduced-mobility riders.
Where the Sardinian project diverges most sharply from other European hydrogen trains is the fuel itself. Trains running in Germany – Alstom's Coradia iLint in Lower Saxony, or the newer Siemens Mireo Plus H in Bavaria – refuel at conventional stations with no guaranteed control over how that hydrogen was produced. Stadler has not yet published an autonomy figure for the narrow-gauge variant, noting that range will depend on line profile and load conditions, but the trains are designed to operate on non-electrified lines currently served by diesel units.
ARST is taking a different approach. It will generate its own hydrogen entirely through solar-powered electrolysis, integrating the production plant directly into the transport network. The result is a system that produces no emissions at any stage, from solar energy generation through electrolysis to propulsion – something no active hydrogen rail project in Europe currently achieves.
"These vehicles, developed in collaboration with Stadler, are a central element of the decarbonization strategy for the narrow-gauge network," said Carlo Poledrini, ARST's Central Director. "It is the first step in ARST’s evolution from a transport operator to an energy company capable of powering its own network of services. As already demonstrated by the active construction sites in Mandas, Alghero and Macomer, we are integrating technological innovation in vehicles with the autonomous production of clean energy."
ARST has ordered 10 trains under a framework agreement signed with Stadler in 2023. Together, they are projected to eliminate more than 2,100 metric tons (2,315 short tons) of CO2 per year compared to the diesel units they replace. That’s equivalent, according to Stadler, to roughly 450 car trips around the globe.
Sardinia is not an isolated pilot. The Italian government and the Ministry of Infrastructure and Transport have backed a broader initiative to decarbonize narrow-gauge rail across the South. Stadler is also building nine units for Ferrovie della Calabria and two more for Ferrovia Circumetnea in Sicily. All must complete certification by Italy's national rail safety agency, ANSFISA, before entering service.
The first units are scheduled to reach passengers in 2028 on three lines in northern Sardinia: Alghero Airport to Mamuntanas, Sassari to Alghero, and Sassari to Sorso.
Source: Stadler
