Case Study: Hydrogen on the Rails: Germany's Coradia iLint Fleet, a milestone marred with growing pains.

Germany's Coradia iLint hydrogen trains, developed by French company Alstom, made history in 2022 as the world's first full fleet of hydrogen-powered passenger services. They entered operation in Lower Saxony to replace diesel powered trains on non-electrified rural routes. Fast-forward to late 2025, and the project, once hailed as a zero-emission triumph, is grappling with real-world hurdles, including fuel-cell shortages that have sidelined a large proportion of the 14-train fleet. Yet even amid these setbacks, the iLint remains a vital proof-of-concept: fuel cells combine hydrogen and oxygen to generate electricity, emitting only water vapour, while slashing noise and local pollution on lines ill-suited to overhead wires.

The promise? Avoiding ~4,400 tonnes of CO₂ annually (based on full-fleet estimates) and 1.6 million liters of diesel, or the equivalent to powering 1,000 homes for a year. But as Alstom pauses further hydrogen development in key markets like France, the iLint underscores a broader truth: hydrogen rail is innovative, but far from ready to displace diesel at scale without massive green hydrogen investment.

So, what does this mean for decarbonising the rest of Europe's railways?

How the iLint Works:

At its core, the iLint is a hybrid: onboard fuel cells produce ~200 kW of electricity from stored hydrogen (up to 26 kg per tank), powering traction motors and charging lithium-ion batteries for acceleration, braking recapture, and short gaps. No catenary needed (an electrified railway system that uses a network of overhead wires to supply power to trains via a pantograph); range hits 600–1,000 km at 140 km/h top speed, which matches diesel performance without the fumes or associated noise pollution.

This tech shines on Lower Saxony's ~120 km of branch lines, where low passenger volumes (under 1,000 daily) make the cost to electrify the railway lines completely uneconomical. Operators like EVB report 80–90% energy efficiency (vs. diesel's 30–40%), quieter rides, and zero local NOx/PM emissions, a huge positive for rural communities where the trainlines operate.

Why It Matters: Tangible wins in a tough sector

The need to decarbonise train travel is urgent. It accounts for ~2% of global CO₂, but electrifying the remaining 40% non-wired km (often rural or freight) is a €500 billion challenge...

The iLint addresses this head-on:

1. Diesel Dodge for Hard-to-Reach Lines: On routes like Buxtehude–Cuxhaven, it sidesteps catenary costs while delivering diesel-like uptime (initially 95%+ availability). Germany's DB aims for net-zero by 2040; hydrogen fills gaps where batteries fall short on long hauls.

2. Proven Reductions, Real-World Impact: The fleet's projected savings - 4,400 tonnes CO₂/year - equate to removing 1,000 cars from roads annually. Noise drops 10–15 dB, boosting local quality of life.

3. Part of a Broader Toolkit: Not a solo act, pairs with Deutsche Bahn's €30 billion electrification push, battery hybrids, and biofuels.

The Reality Check: Why hydrogen isn't scaling just yet

The iLint's story isn't all steam (or vapor): 2025 exposed vulnerabilities, with EVB reverting to diesel for 70% of services amid fuel-cell delays, a stark reminder that prototypes don't always translate to fleets.

Broader hurdles persist:

• Hydrogen's "Green" Catch: Benefits evaporate with grey hydrogen (90% of supply; 10 kg CO₂/kg H₂ produced). True zero-emission needs electrolytic "green" H₂ from renewables – but EU capacity is just 2.5 mtpa in 2025, vs. 20 mtpa needed by 2030. Cost: €3–5/kg now, targeting €1–2/kg.

• Infrastructure Overhaul: Refueling stations cost €10–20 million each (plus safety regs); Linde's mobile units in Lower Saxony work for pilots but scale poorly. Depot upgrades add 20–30% to capex.

• Economics vs. Alternatives: Lifecycle costs 50–80% higher than batteries (€15–20m/train vs. €10–12m) or full electrification (€5–7m/km but €0.05–0.07/kWh ops). Batteries suit 80% of branch lines (range 100–200 km, 5–10 min charge); hydrogen edges out for freight/long rural (efficiency 40–50% vs. batteries' 80–90%).

• Supply Woes: Global electrolyser shortages (up 50% in 2025) and Alstom's R&D pause signal scaling risks.

Hydrogen's Niche: Not a bullet, but a bullet point

Hydrogen has a credible niche: non-electrified regional lines, freight on routes where battery solutions struggle, and as part of broader sector decarbonisation where rail electrification is prohibitively expensive. The iLint proves the technology can run reliably in passenger service and deliver measurable CO₂ reductions and quieter journeys. But turning that niche into mass deployment requires aligning hydrogen production, infrastructure investment and long-term policy support.

Expect hydrogen on 5–10% of global non-electrified routes by 2035, rural passengers/freight where batteries lag and wires won't pay. The iLint proves viability (if green H₂ flows), but success hinges on € billions of European-wide investment in production and accompanying infrastructure by the 2030s.

Lessons for the UK: Seize the niche but lets leave the hype at home

The UK's 2040 diesel ban leaves 40% of tracks non-wired, prime for hydrogen, but trials like HydroFLEX (converted Class 319) remain prototypes, with no firm orders by late 2025. Network Rail's £2.5 billion battery push for branches shows the path. The lesson is to prioritize H₂ for Tees Valley freight or Scottish Highlands passengers:

• Match Tech to Terrain: Hydrogen for low-traffic rural (e.g., Cumbria lines); batteries/electrification elsewhere.

• Lock in Green Supply: Mandate low-carbon H₂ via 2026 standards; leverage North Sea hubs.

• Centralize Infra: Fund clustered depots (€500m national program) for scale.

• Stay Neutral: Blend with £10 billion Great British Railways electrification – route audits first.

Verdict: A small, but vital component, for rail decarbonisation efforts

The Coradia iLint is an important proof-point: hydrogen trains can operate reliably, quietly and with genuine local emission reductions. Germany’s deployment in Lower Saxony is both symbolic and practical...a demonstration that, with the right investments, diesel can be replaced on branch lines today.

But hydrogen is not the big answer for rail networks to achieve net zero.

The ultimate contribution of hydrogen to rail decarbonisation will depend on whether governments can scale green hydrogen fast enough, build refuelling infrastructure, and make the right policy choices about which routes are best served by catenary, battery or fuel cell.

The iLint is a milestone, but it should be read as one piece of a diversified, technically realistic pathway toward climate-neutral rail, not as a single solution to the sector’s decarbonisation challenge.