No diesel, no overhead wires – How India’s hydrogen train actually works

A train pulls into a station without the familiar rumble of a diesel engine or a cloud of exhaust. Instead of burning fuel to move, it carries a system that produces electricity inside the train itself. The fuel is hydrogen, and the only direct by-products of the process are water and heat.

India has already taken this technology out of the drawing board. Its first hydrogen-powered passenger train named “Namo Green Rail” was flagged off on 17 July 2026, on the Jind-Sonipat section in Haryana. The 10-coach train has two hydrogen-powered driving units, eight passenger coaches and a combined power output of 2,400 kilowatts.

But hydrogen does not directly turn the train’s wheels. It first has to be converted into electricity through a device called a fuel cell. Understanding that process also explains why hydrogen trains are being explored as an alternative to diesel locomotives, and why they are not necessarily the answer for every railway route.

It is an electric train, but it carries its own power station.

The easiest way to understand a hydrogen train is to think of it as an electric train that does not need overhead wires to draw electricity.

A conventional electric locomotive receives power from overhead lines or, in some systems, a third rail. A hydrogen train generates electricity onboard. It does this using a fuel cell, which combines hydrogen stored in tanks with oxygen drawn from the surrounding air.

Inside the fuel cell, hydrogen molecules are split into protons and electrons. The protons pass through a special membrane, while the electrons travel through an external circuit. That movement of electrons creates an electric current.

The electricity is then used to power traction motors, which turn the wheels and move the train. Water and heat are produced during the reaction.

The process can be represented simply as:

Hydrogen + Oxygen => Electricity + Water + Heat

There is no burning of hydrogen in an engine. Instead, the fuel cell converts its chemical energy directly into electrical energy.

This is why a hydrogen train is technically an electric train, even though it does not rely on an overhead power supply.

Why does it also need a battery?

If the fuel cell produces electricity, why does the train need batteries as well?

The answer lies in the way trains use power. They do not require the same amount of electricity at every moment. Starting from a station, accelerating, climbing a gradient and travelling at speed can all place different demands on the propulsion system.

A fuel cell is well suited to supplying a relatively steady stream of electricity. A battery, meanwhile, can provide additional power when demand rises sharply.

India’s train uses lithium iron phosphate batteries alongside its hydrogen fuel cells. The two systems work together: the fuel cells provide electricity, while the batteries help meet sudden increases in power demand and store surplus energy when available.

The batteries can also capture energy during braking through regenerative braking, converting some of the train’s motion back into electricity rather than losing all of it as heat.

In India’s train, the propulsion equipment is housed in two driving power cars, one at either end of the eight passenger coaches. Each has a rated output of 1,200 kW, taking the combined output to 2,400 kW.

The train is approved to operate at up to 75 kmph on the Jind–Sonipat route, although its design speed is 110 kmph.

Where does the hydrogen come from?

A hydrogen train cannot simply collect hydrogen from the air. It needs a dedicated production, storage and refuelling system.

At Jind, Indian Railways has established a facility to supply hydrogen to the train. The hydrogen is produced through electrolysis, a process in which electricity is used to split water into hydrogen and oxygen.

The hydrogen is then compressed and stored in specialised tanks. This is necessary because hydrogen is a very light gas and occupies a large volume unless compressed.

At the Jind facility, the storage system can hold around 3,000 kg of hydrogen. The gas is stored at pressures of up to 500 bar and dispensed to the train at 350 bar through dedicated refuelling equipment.

The arrangement is similar in principle to refuelling a conventional vehicle, but the pressures, storage equipment and safety procedures are very different.

The train’s onboard cylinders carry the hydrogen to the fuel cells, where it is converted into electricity during the journey.

If hydrogen is flammable, how safe is the train?

Hydrogen is highly flammable. It can ignite when mixed with air in the right proportions, and storing it under high pressure introduces additional engineering challenges.

That does not automatically make hydrogen transport unsafe, but it means the entire system has to be designed around preventing leaks, detecting them quickly and controlling the supply if something goes wrong.

Indian Railways has installed sensors to detect hydrogen leaks, heat, flames and smoke. The train also has ventilation systems, automatic shut-off arrangements and monitoring equipment. The refuelling facility is subject to safety procedures and has received approval from the Petroleum and Explosives Safety Organisation.

The gas is stored in specialised cylinders, while the supply system is designed to isolate the hydrogen flow if abnormal conditions are detected. These safeguards are important because hydrogen is difficult to contain: its small molecules can escape through gaps that would not necessarily leak other gases.

The safety challenge is therefore not just about preventing a fire. It is about ensuring that a leak is detected before hydrogen can accumulate in a dangerous concentration.

Is a hydrogen train really emission-free?

At the point where the train operates, a hydrogen fuel cell produces no carbon dioxide from the propulsion process. Its direct by-product is water, rather than the exhaust associated with diesel combustion.

But there is an important distinction between what comes out of the train and the emissions involved in producing its fuel.

Hydrogen is not naturally available as a ready-to-use energy source in the same way that sunlight or wind is. It has to be produced using another source of energy. If the electricity used for electrolysis comes from renewable sources such as solar or wind, the resulting hydrogen can be classified as green hydrogen.

If hydrogen is produced using fossil fuels, however, its production can generate substantial greenhouse gas emissions. The environmental benefit of a hydrogen train therefore depends partly on how the hydrogen is made, how it is transported and how much energy is used along the way.

In other words, a train that emits only water vapour while moving is not automatically carbon-free across its entire energy supply chain.

Why not replace every diesel train with hydrogen?

Hydrogen trains are not necessarily a better option than conventional electric trains. Where overhead electrification already exists, using electricity directly is generally more energy-efficient than converting it into hydrogen, compressing and storing it, and then converting it back into electricity onboard.

That is one reason the technology is particularly relevant to routes where installing overhead wires is difficult or expensive, including some regional and less heavily used railway lines.

Indian Railways has electrified more than 99 per cent of its broad-gauge network, according to the Railways. This means hydrogen is not being introduced to replace the entire electric railway system. Its potential role is more specialised: providing an alternative to diesel on sections where full electrification may not be practical.

There are also questions around the cost of producing green hydrogen, the expense of specialised trains, the construction of refuelling stations and the availability of a reliable supply. These factors will determine whether the technology can be expanded beyond a pilot route.

What happens next?

India’s first hydrogen train is intended to demonstrate that the technology can work under Indian railway conditions. The project also establishes infrastructure for producing, storing, compressing and dispensing hydrogen, rather than testing only the train itself.

In July 2026, the Railways said the train had travelled more than 1,200 km since its launch, saving over 3,200 litres of diesel. It has also indicated that experience from the project could help assess hydrogen-powered trains for other routes, including heritage sections such as Kalka–Shimla.

The technology is still developing, and its wider use will depend on operational reliability, fuel costs, safety and the availability of genuinely low-carbon hydrogen.

The bigger shift is in how a train gets its power. For more than a century, railway propulsion has relied on burning fuel onboard or drawing electricity from an external supply. A hydrogen train offers a third arrangement: carrying a fuel that can be converted into electricity as the train moves.

Whether it becomes a common sight on Indian tracks will depend not just on how well the train runs, but on whether the country can produce enough affordable, low-emission hydrogen to keep it moving.