Swiss locomotive manufacturer Stadler and Sardinia regional public transport operator ARST (Azienda Regionale Sarda Trasporti) recently jointly launched the world's first hydrogen-fuel train specially developed for narrow-gauge railways, marking a key step in the decarbonization path of South Italy's historic railway network. Since narrow-gauge lines have strict restrictions on axle weight, any existing hydrogen-powered train cannot be directly adapted. This new train was designed completely from scratch and uses a lightweight aluminum body to meet the structural and weight requirements of narrow-gauge operations.
The railway network in the regions of Sardinia, Calabria and Sicily dates back to the 19th century and has a gauge of 950 millimeters (about 37.4 inches), significantly narrower than the standard gauge of 1435 millimeters (about 56.5 inches) prevalent in Europe. This difference in gauge results in very stringent axle load restrictions for narrow-gauge lines, which cannot be put into operation simply by retrofitting existing hydrogen-powered trains, forcing Stadler to reshape the car body structure for the network and develop a new lightweight body profile to adapt to the existing track system.
In terms of powertrain, the new train follows the common technical route of European hydrogen railways in recent years: the fuel cell converts compressed hydrogen into electrical energy, charges the traction battery, and then the battery drives the train. However, in terms of system layout, Stadler chose a different solution from some German projects, centrally arranging key equipment such as fuel cells, hydrogen storage systems, and batteries in a dedicated middle car "Power Pack" instead of being scattered on the roof like the standard rail models of Alstom or Siemens. This centralized layout helps free up space in the end and middle compartments for the installation of full-vehicle air conditioning, large-area viewing windows and low-floor structures, providing a more barrier-free ride experience for passengers with reduced mobility.
Compared with the hydrogen-powered trains in operation in Germany, the Sardinia project has achieved a more thorough greening of the source of hydrogen fuel. Current hydrogen trains in Germany, such as the Alstom Coradia iLint in Lower Saxony or the Siemens Mireo Plus H in Bavaria, are often refueled at conventional hydrogen refueling stations, making it difficult to fully control the hydrogen production method and carbon emissions. Stadler has not announced the specific cruising range of this narrow-gauge hydrogen train, saying only that its cruising range will depend on the line gradient and passenger load. However, it is clear that the new trains will be mainly deployed on branch lines that are currently undertaken by diesel multiple units and have not yet been electrified.
ARST adopts a completely different strategy: it plans to use solar energy to drive a water electrolysis device, independently produce all the hydrogen fuel required for operation, and embed the hydrogen production plant directly into the regional transportation network. This means that the entire chain from solar power generation, electrolytic hydrogen production to train power output achieves "full-process zero emissions", which is the first of its kind in the current European hydrogen railway project. Carlo Poledrini, Central Director of ARST, said that these trains are a core component of the decarbonization strategy of the narrow gauge network and an important starting point for ARST to transform from a single transport operator to an enterprise with self-sustaining energy capabilities. By advancing construction in places such as Mandas, Alghero and Macomer, they are deeply integrating technological innovation on the vehicle side with autonomous clean energy production.
ARST has ordered 10 narrow-gauge hydrogen-powered trains from Stadler under a framework agreement signed in 2023. Both parties estimate that after these trains are put into operation, they can replace existing diesel-powered vehicles and reduce carbon dioxide emissions by more than 2,100 tons (approximately 2,315 short tons) every year, which is equivalent to the total emissions of approximately 450 round-trip car journeys around the world. The Sardinian project is not an isolated pilot. The Italian government and the Ministry of Infrastructure and Transport are promoting the wider decarbonization of the southern narrow-gauge railway system. Stadler is also supplying 9 similar trains to the Calabria Railway Company (Ferrovie della Calabria) and 2 new trains to the Ferrovia Circumetnea in Sicily. All the above-mentioned vehicles must pass the certification process of ANSFISA, Italy's national railway safety agency, before they can officially carry passengers.
According to the current timetable, the first narrow-gauge hydrogen-powered trains are expected to enter passenger service on three lines in northern Sardinia in 2028, including the Alghero Airport to Mamuntanas, Sassari to Alghero and Sassari to Sorso sections. With the advancement of vehicle production and the completion of supporting solar hydrogen production facilities, the narrow-gauge railway network in southern Italy is expected to gradually wean itself off diesel power in the next few years, providing a new zero-emission solution for European regional railway systems that combines technological innovation and energy self-sufficiency.