mar 9, 2026 - (POLAND) Diesel-Hydrogen Multiple Unit Retrofit unveiled in Poland

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The diesel engine in one car of a two-car DMU has been converted to run on hydrogen.

Photo Credit: Digas/Natalia Momot
THE partners in the European Union (EU)-funded Hyiptrain project, which is developing solutions to convert DMUs to run on hydrogen rather than diesel fuel, have presented the first completed prototype.

The two-car DM90 DMU was presented at a depot in Zagorz, southeastern Poland, owned by Polish operator SKPL Cargo. It has been converted to run on both fuels under the project, with one car continuing to run on diesel and the second car’s internal combustion engine converted to burn hydrogen. The conversion took around 45 days to complete with commissioning and testing taking place over a two-month period.

The project was implemented by Latvian company Digas as lead partner together with Mikroluch, Ukraine. Digas was responsible for overall system integration and certification, with Mikroluch providing specialist expertise in embedded control systems for internal combustion engines powered by alternative fuels.

According to Digas, the prototype has been equipped with three hydrogen tanks, which provide a range of 60km when operating solely on hydrogen fuel. Mobile refuelling takes places via a truck certified to carry hazardous materials.

Trials
Demonstrations have been taking place between Zagorz and Ustrzyki Dolne as well as Zagorz and Targowiska in Poland. Under a complete conversion, 22 hydrogen tanks would be installed to offer a range of 440km on hydrogen alone. A single train could operate on the line three times per day and would require refuelling every two days, Digas says.

Grey hydrogen fuel has been used during the test phase with the tests revealing reductions in NOx emissions of more than 83% compared with a target of up to 60%. Particulate matter emissions were also reduced by around 96% compared with a target of up to 90%, while exhaust CO₂ emissions were eliminated entirely with hydrogen.

Digas told IRJ that temporary authorisation has already been secured for the train to operate on the main line, with work on full certification now underway and expected to be completed in six months. The objective is to introduce the train into commercial service in Poland. However, Digas’ head of business development, Robert Strods, says viability is dependent on the cost of hydrogen compared with diesel. “Right now, the cost of green hydrogen is much higher than diesel fuel, around two to two-and-a-half times,” he says. “If that gets down to 1.2-1.5 times, it could be interesting for the industry.”

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