If Europe is committed to a series of measures that generalize the use of hydrogen, the railway network is also opening its hydrogen sector. Today, several players (large groups, small businesses, or start-ups) are launching numerous innovative projects in this sector.

 Hydrogen giant Alstom, Engie’s new partner

On April 6th, Alstom and Engie signed a partnership agreement to offer a decarbonization solution for rail locomotives based on renewable hydrogen.

Alstom will contribute its expertise in hydrogen mobility by designing a high power hydrogen fuel cell system. These fuel cells will power electric locomotives in non-electrified areas.

“Our ambition is to accelerate the adoption of hydrogen in the rail industry and to develop innovative solutions as part of the greening of heavy mobility, including rail freight. To develop the hydrogen sector, we need to mobilize all the players in this sector. This is the meaning of our partnership with ENGIE,” says Raphaël Bernardelli, Vice President of Corporate Strategy at Alstom.

Engie, a leader in energy transition and a pioneer in renewable gases, will supply the renewable hydrogen for this solution through the deployment of an innovative supply chain.

This partnership will provide a low-carbon, zero-emission solution in response to climate change issues, including on non-electrified branch lines and sidings. The target market is the major European rail freight countries.

Indeed, half of the European rail network is still not electrified. The diesel consumption of freight trains is therefore very high : several hundred million liters per year in some cases.

Some partners are already counting on several orders for fuel cells, to be put into service by 2025.

Others could follow quickly, since the SNCF, which plans to double its share of the freight transport sector by 2030, is also considering banning the use of diesel fuel by 2035.

The emergence of composites in rail

In 2012, despite the strong demand for composite in rail, the lack of knowledge and experience on structural elements did not allow for the use of composite at 100%.

That is why the European Railway Industry Association, launched in September 2013 the European project REFRESCO. This project, which included a dozen partners such as Bombardier, Alstom, SNCF, Siemens, Talgo, Dupont, CAF had the ambition to evaluate the possibilities of using composites in the structural parts of trains.

The results of this project were very encouraging. They showed that composites had a place in the structural part (locomotives or wagons).

Moreover, many advantages were noted such as : lightening of the structures but also a better resistance to impact and a reduction of the maintenance needs.

In response to the positive feedback from these projects, numerous initiatives have been launched, such as the Roll2Rail project, and a collective European technological initiative for railways, Shift2Rail.

The aim is to create demonstrators and to set up appropriate certification.

Promising results 

Thanks to their lightness and high resistance, the use of composite materials has become essential in the railway industry, as Tanguy Choupin points out : “If the first uses of these materials for train trim parts date back to the 1960s, the use of composite materials for the so-called structural parts of the train, its skeleton, is a great novelty.

Thus, since February 2021, a composite sleeper has been tested on a TER 2N NG train in commercial service. In addition to saving 43% in weight compared with a metal sleeper, the use of composite materials also improves the strength and lifespan of the parts. “If our composite parts hold up longer than metal parts, it could allow for lighter maintenance which would translate into lower ticket prices for passengers. That’s the promise of these materials, which needs to be verified in the field.

In addition, a new composite fairing has also been tested since April 2021 on the INOUI and OUIGO TGVs. The change in the shape of the part will allow for gains in aerodynamics and energy efficiency, avoiding 537 tons of CO2 emissions per year.

The use of these new composite materials for the nose of the TGV will also make the fairing more resistant to light impacts and therefore reduce the number of discarded parts. By 2028, 95% of double-deck TGVs should be equipped with this new nose.

New composite tanks for hydrogen transport

New technologies for storing hydrogen in tanks have recently been created. These pressure tanks will be used for both fixed and mobile applications, including

• Hydrogen storage infrastructure
• Hydrogen transportation for refueling
• Hydrogen rail vehicles
• Buses, trucks and other hydrogen vehicles
• Hydrogen cars.

Composed of composite materials, they have significant advantages over other pressure tanks.

First of all, the carbon fiber reinforced structure generates a better strength/stiffness/weight ratio. This represents a potential weight saving of about 450 kg for gas containment systems on buses and trucks.

In addition, this structure contributes to a significant optimization of fuel consumption.

And finally, the use of pressure vessels offers further advantages in terms of durability and chemical resistance as they are transparent to X-rays and do not expand when heated.