Latvian Technology Lets Existing Passenger Trains Run on Hydrogen
A Latvian-built control system now lets diesel passenger trains already in service be converted to hydrogen internal combustion, at a fraction of the cost of new rolling stock. It reopens the decarbonisation case for the 43% of EU rail that electrification never reached — and puts Latvia on the export side of the hydrogen economy.
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8/21/20263 min read
There's a version of rail decarbonisation that never quite adds up. You look at a regional line with no overhead wires, count the diesel units running on it, check the price of a new hydrogen train — and quietly put the file back in the drawer. That has been the story on a lot of European track. A Latvian engineering company has just changed the arithmetic.
The missing piece of the retrofit kit was software
SIA DiGas has developed an electronic control system — the technology's "brains" — that allows diesel passenger trains already in service to be converted to run on hydrogen in an internal combustion engine. The work was carried out inside the MASOC Competence Centre's digital products programme. According to MASOC, this control layer was the component the whole conversion package had been missing: it automates and coordinates fuel injection, combustion control and safety functions, tying mechanical hardware to digital systems through artificial intelligence and data analytics algorithms.
Everything else in a hydrogen conversion — tanks, injectors, engine modifications — has existed in some form for years. The control system is what makes those parts behave as one machine, safely, under real service conditions. That is the part nobody had finished.
Replacement maths that never closed
Roughly 7,200 diesel passenger trains run in Western Europe alone, and the average train stays in service around twenty years. Do the division. Even with steady orders for new hydrogen rolling stock, only a small slice of the fleet turns over each year — which leaves the large majority with no realistic renewable fuel option for decades.
DiGas puts its conversion at roughly twenty times cheaper than buying a new hydrogen train. That is the company's own figure and worth verifying against a specific conversion contract, but even at a fraction of the ratio the logic holds: retrofit reaches fleets that procurement budgets never will. The emissions case is concrete. Particulate matter falls close to zero, nitrogen oxides drop by about 70%, and the engine runs considerably quieter.
The part of Europe's network the wires never reached
Only 57% of EU rail lines are electrified. The remaining share is not unelectrified by oversight — those are lines where catenary has never been justified by the traffic running on them. Regional corridors, low frequencies, long gaps between towns. That is the profile of a good deal of Baltic track outside the Rail Baltica corridor.
For Latvian hydrogen ecosystem stakeholders that is the honest starting point. Rail Baltica will be electrified from day one. The existing 1520 mm network and the regional services on it will not be, not comprehensively and not soon. A retrofit route to hydrogen turns those lines from a decarbonisation dead end into a demand centre — and demand is the thing almost every hydrogen production plan in this region is short of.
Latvia's hydrogen value sits in the equipment, not only the molecule
The system will be manufactured in Latvia, and DiGas is targeting €34.2 million in cumulative export revenue by 2031. That number deserves more attention than it usually gets. Most national hydrogen strategies in this region are written around production — electrolysers, renewables, offtake agreements. Far fewer are written around selling hydrogen technology to everybody else.
DiGas has been building toward this for some time. The company signed with Iarnród Éireann in 2023 to trial what was billed as Europe's first retrofitted hydrogen internal combustion freight locomotive, and it has since partnered with France's HDF Energy on hydrogen locomotive development. The passenger result now claims a European first of its own: the first retrofitted hydrogen internal combustion engine passenger train on the continent.
There is a second thing worth naming, and it is the support mechanism. The research was delivered through a competence centre programme financed by the EU Recovery and Resilience Facility. DiGas board member Petro Dumenko credits that structure with supplying not only financial leverage for the research but influence and discipline that helped finish the project at high quality and faster than originally planned. Public money that buys engineering rigour rather than simply paying invoices is a model Baltic hydrogen stakeholders should be pointing at more often.
What this changes for Baltic hydrogen planning
Non-electrified regional lines become a credible near-term offtake candidate rather than a long-dated maybe.
Retrofit economics move the conversation off rolling-stock procurement cycles and onto fleet conversion programmes — a different budget line, and a far shorter timescale.
Latvia now has a reference case for exporting hydrogen technology, not only for planning hydrogen production.
The competence centre route shows a workable path from research idea to commercial product for other Baltic hydrogen developers.
None of this puts a hydrogen train into Latvian service on its own. Supply, refuelling infrastructure and certification are all still open questions here, and they will not answer themselves. But the technology's centre of gravity has moved closer to home, and that changes what is reasonable to plan for.
Source: Latvijā radīta tehnoloģija, kas ļauj pasažieru vilcieniem braukt ar ūdeņradi