LATVIAN group Digas is seeking partners for a project to convert the diesel internal combustion engine of a DMU to use hydrogen fuel. Digas has received European Union (EU) funding for the demonstration project and is looking to build on similar work already underway with Irish Rail (IÉ) to convert a class 071 locomotive to run on hydrogen.

Digas has secured a €600,000 grant from the EU’s EIT Urban Mobility fund for the project, which is expected to be completed by late 2025 or mid-2026. A further €350,000 has been secured from Latvia’s Competence Centre, which is part of the Ministry of Economy, using funding from the National Recovery Facility.

Prospective partners are expected to contribute €350,000 to the project, taking the total budget to €1.3m.

The terms of the project stipulate that it must be a retrofit of a legacy diesel passenger train, must use hydrogen fuel, and focus on an internal combustion engine conversion rather than a fuel cell solution used in new-build hydrogen trains such as Alstom’s iLint, the Siemens Mobility Mireo Plus H and Stadler’s Flirt H2. The objective is to offer a pathway to a more affordable alternative for operators to convert their DMU fleets to hydrogen.

Mr Robert Strods, head of business development at Digas, told IRJ that he has been in discussion with British, Swedish and Lithuanian-based operators and fleet owners about working together on the project, but has yet to conclude a formal partnership agreement.

“We must secure a partner within the next three months otherwise we will lose the funding,” he says.

Strods says that although they will consider any type of DMU, his preference is to convert an Alstom Lint DMU, which makes up around 70% of Europe’s DMU sales in the past decade or so. He says the plan is to adopt many of techniques and technologies used in the iLint, including using the same suppliers of fuel cylinders and piping, with the only major difference being the use of the existing internal combustion engine rather than a fuel cell. “Everything else will be the same as in iLint,” Strods says.

He adds that the project envisages converting a DMU equipped with two engines as this is the most widely-used configuration. “We can extend to three but this would require an increase in the co-financing from the operator, although not substantial and probably around 25%,” Strods says.

He adds that another option proposed by a prospective partner is to convert one of the two engines and leave the other as a back-up “at least during the demonstration period.”

If a British rolling stock leasing company comes forward, Strods expects the project to develop a similar approach to the HydroFlex project developed by Porterbrook, which converted  a class 319 EMU into a tri-mode train operating under electric, battery and hydrogen power. A fuel cell-based solution was used here with hydrogen fuel stored in tanks in one of the passenger cars. “The restricted loading gauge means we are unable to store the hydrogen on the roof of the train,” Strods says.

The converted train is expected to offer a range of 400km, around half of the iLint. However, Strods says this is reflective of the project’s status as a demonstrator rather than the limitations of conversion to hydrogen fuel. He says the project will aim to show that using hydrogen as the fuel source can offer the same output and torque as a diesel engine.

“We will do this initially on a test bench as we have been doing on the Irish project before the train offers on-track demonstrations,” Strods says.

He adds that the owner of the demonstration unit will be free to use the train for further trials or to even reintroduce it into service following the conclusion of the project.

Expanded team

Digas is a relatively small outfit, employing just 14 people, with the company’s technical teams currently “fully immersed” in the Irish project, according to Strods. However, as work on the research and development phase of this project comes to an end and transitions to production, much of which will be outsourced, these engineers will be available to work on the passenger hydrogen retrofit. “Part of the team will be available and we expect that another five or six people will be required,” Strods says.

Under the €1.5m project with IÉ, Digas is manufacturing, delivering and installing the hydrogen internal combustion engine retrofit on the class 071. IÉ is providing workshop space for installation, testing and commissioning activities and will test the retrofitted locomotive. IÉ is also working to identify project partners that will provide hydrogen refuelling equipment. Strods says he hopes that the passenger project will take on a similar approach.

Work with IÉ commenced in September 2023 and the main challenge has been extended lead times for the hydrogen components, according to Strods. However, he is encouraged by overall progress. “We hope that the locomotive will be ready for line testing by September to coincide with InnoTrans,” he says. 

To learn more about Digas’ work to convert internal combustion engines to use hydrogen fuel, see the feature in the October 2023 edition of IRJ. Online subscribers can also read the article here.