Hydrogen trains are set to revolutionise the rail network.

A government imposed deadline to rid the rail network of diesel powered trains by 2040 has propelled the new technology to the fore.

The technology is already being eyed up by the new Wales and Borders railway franchise, with plenty more interest growing across the country.

But how does it work and where can the potential be maximised?

Train manufacturer Alstom recently announced its plans to bring hydrogen trains to the UK, working with Eversholt Rail to convert Class 321 trains from electric to hydrogen. But its ambitions are much loftier. Alstom aims to convert around 2,500 diesel trains which currently serve the lower speed and less densely packed routes and meet the clean air and zero carbon targets.

“If we look at the UK market, what we’re particularly focused on are the areas which were never intended to be electrified,” says Alstom head of business development and marketing Mike Muldoon.

“The driver for this is how we address transport routes that are currently served by diesel and would never be economically viable for electrification – the lower speed and lower densely packed routes.”

The work here is building on work Alstom has already done in Germany. There it is just about to put two new Coradia iLint hydrogen fuelled trains into service with an order for 14 more to be delivered by 2021 and 2022 together with the infrastructure needed to refuel the trains.

If the UK conditions are favourable then a fleet could be deployed here on the same three-to-four-year timescale he says.

To introduce the trains into the UK, a rigorous approvals process will have to be carried out. This would address safety concerns about using the highly combustible hydrogen as a fuel.

But Muldoon says hydrogen, handled correctly, is no more dangerous than the many other combustible fuels already carried on cars, planes and tankers on the road.

“One of the things we’re doing at the moment is making sure that all of the expertise from handling, transport and storage is used,” he says. “We’re not going to reinvent the wheel and we’re working closely in the field to use the safest technology.

“Gas is transported at pressure on the road, we have buses and cars with this issue already and we also have gases transported as freight on trains, so none of this is new.”

He says that Germany’s hydrogen trains have on board systems that will shut down the train and make sure the gas is contained should a problem arise.

The trains will be able to travel around 1,000km a day without refuelling -– comparable to the range of a diesel train.

To power the train, the new technology uses a combination of a fuel cell and a lithium ion battery.

The fuel cell produces electricity through an electrochemical reaction of hydrogen and oxygen, creating water as a by-product. The batteries are used to store energy recycled from braking when the train decelerates.

When working out how many journeys a train will be able to carry out, factors such as topography, number of stops and nature of the service will all be taken into account. Systems on board the trains will also give feedback to the driver to make sure they are driven in the most efficient way.

Muldoon says that in future the hydrogen making process could become zero carbon by using unused renewable energy. At present however, he says there’s a plentiful supply of hydrogen made as a by-product in the chemical industry.

“If you use the renewable energy which isn’t currently used or can’t be accepted by the grid, to produce hydrogen, from the creation of the fuel right through to the motion of the vehicle you have no emissions from well to wheel,” he says. “That is the preferred outcome and that is why hydrogen is so attractive to the transport sector right now.”