Hydrogen Train for Narrow Gauge: Switzerland and Italy Solve Decades-Old Rail 2026

Switzerland and Italy have just solved a decades-old problem: fitting a hydrogen train onto narrow-gauge tracks. Stadler and ARST presented what they call the first hydrogen train designed specifically for narrow-gauge railways at an event in Erlen, Switzerland. The train is slated to begin passenger service in 2028 on three lines in northern Sardinia.

This breakthrough matters because narrow-gauge networks, common in mountainous regions and islands, have long been stuck with diesel traction due to space and weight constraints. The new design opens a path to zero-emission rail on routes that were previously off-limits to hydrogen technology.

What Happened: A Project Years in the Making

The Swiss manufacturer and ARST have completed a project that began with a framework agreement signed in 2023. That agreement covers the supply of ten hydrogen trains for the Sardinian network. According to the press release, these vehicles will replace current diesel units and are expected to save more than 2,100 tonnes of CO2 per year. Stadler compares that reduction to avoiding about 450 car trips around the planet.

The first train was unveiled in Erlen, where Stadler has its headquarters. The event marked the culmination of engineering work that had to overcome significant technical hurdles. The trains will enter service on three lines in northern Sardinia, a region that relies heavily on its rail network for local mobility.

Why It's a Technical First

Until now, hydrogen trains operating in Europe, such as Alstom's Coradia iLint in Lower Saxony or Siemens' Mireo Plus H in Bavaria, have been developed for standard-gauge tracks of 1,435 millimeters. Sardinia, Calabria, and Sicily, however, retain a network inherited from the 19th century with a gauge of only 950 millimeters. That narrower gauge imposes much stricter axle-load limits.

To fit within that reduced space, Stadler had to design a completely new lightweight aluminum body. The smaller gauge means less room for hydrogen tanks, fuel cells, and other components, so every kilogram counts. The new design ensures the train can operate safely on tight curves and lightweight track structures without compromising performance.

The Weight and Space Challenge

Narrow-gauge railways often traverse rugged terrain with sharp curves and steep gradients. The train's lightweight construction is not just about meeting axle-load limits but also about maintaining stability and efficiency on these challenging routes. The aluminum body helps reduce overall weight while maintaining structural integrity.

Hydrogen Storage and Range

Although specific range figures were not disclosed, the train will need to carry enough hydrogen to cover the Sardinian routes without frequent refueling. The compact design of the fuel cell system and storage tanks had to be adapted to fit the smaller loading gauge. This engineering feat demonstrates that hydrogen propulsion can be scaled down for smaller rail applications.

Environmental Impact and Regional Benefits

The expected savings of over 2,100 tonnes of CO2 annually represent a significant step toward decarbonizing rail transport in Sardinia. The region's narrow-gauge lines are often used by commuters and tourists alike, and replacing diesel trains with hydrogen-powered ones will improve air quality and reduce noise.

For ARST, the project aligns with broader European goals to cut emissions from transport. The ten trains will be deployed progressively, with the first three lines in northern Sardinia slated for 2028. This move could serve as a model for other narrow-gauge networks in Italy and beyond.

• First hydrogen train for narrow-gauge tracks developed by Stadler and ARST.
• Ten trains ordered under a 2023 framework agreement.
• Over 2,100 tonnes of CO2 saved annually compared to diesel.
• Service starts in 2028 on three lines in northern Sardinia.
• New lightweight aluminum body designed to meet strict axle-load limits.

Comparison with Existing Hydrogen Trains

The table below highlights key differences between the new narrow-gauge train and existing hydrogen models in Europe.

The comparison underscores the novelty of the Stadler-ARST project: it is the first to adapt hydrogen propulsion to a significantly narrower gauge, which required a ground-up redesign rather than a modification of existing standard-gauge trains.

What to Watch Next

While the unveiling is a milestone, several steps remain before passengers can board in 2028. The trains must undergo rigorous testing on the narrow-gauge network, including trials on gradients and curves typical of Sardinian lines. Refueling infrastructure also needs to be built or adapted to support hydrogen operations. The background to this story is set out in Andy Burnham Aims to Solve Social Care Crisis After Decades. A related thread runs through Car: latest articles. Earlier coverage in Spain Rejects EU Plan to End Iberian Rail Gauge Exception shows how the argument developed.

Additionally, the project's success could influence other regions with narrow-gauge networks, such as parts of Switzerland, Spain, and Japan. If the Sardinian deployment proves reliable and cost-effective, it may accelerate the adoption of hydrogen trains on non-standard tracks worldwide. A closer look at the same subject appears in Rail Expert Salvador Galve Chooses Car Over Train for Zaragoza-Barcelona. Anyone following the wider picture can start with Óscar Puente Resigns as Spain's Transport Minister After Deadly Train Crashes. The same theme surfaces in Spain Train Crashes Erode Public Trust in Rail Network, which takes a different angle.

Stadler and ARST have not yet announced the exact routes or the cost of the trains, but the framework agreement suggests a long-term commitment. As the first of its kind, this train represents a significant leap in making rail transport more sustainable across diverse rail systems. Context on how this played out before sits in Spain Train Crash: Minister Weighs Extra Passive Safety Measures. A companion piece, Hydrogen Train for Narrow Gauge: Switzerland and Italy Solve Decades-Old Rail, approaches the same subject from another angle.