Although electric trains have long been viewed as the most likely successor to the existing diesel fleet across Europe and elsewhere, efforts to roll them out on a large-scale are often hampered by the need to invest in expensive electrical rail infrastructure. In recognition of this limitation, a growing number of companies are actively developing hydrogen-powered trains capable of running on the existing rail infrastructure.

One of the early trailblazers in this area is German company Siemens Mobility, which has developed the Mireo Plus H hydrogen train, a two-car commuter train with a state-of-the-art hydrogen drive system consisting of a fuel cell and a lithium-ion battery. According to the company, the Mireo Plus H will be as powerful as a conventional electric multiple-unit train and have an operating range of up to 800 km, depending on operating conditions such as the season or the route. An additional three-car version will have a range of 1,000 km.  

Other distinguishing features of the train include its low lifecycle costs, achieved as a result of low maintenance and repair costs, and a top speed of 160 km/h. As Jochen Steinbauer, Head of Hydrogen Trains at Siemens Mobility, explains, in hydrogen drive systems using fuel cell technology, the reaction of hydrogen and oxygen produces electricity and water, meaning that the Mireo H Plus ‘can be used as a way to become climate-neutral by replacing diesel-powered trains with alternative drive systems.’  

‘To ensure the solution is truly eco-friendly, green electricity should be used to produce the environmentally-friendly green hydrogen,’ he adds.

According to Siemens, the Mireo Plus H will start testing in Baden-Württemberg in 2023. In the following year, as part of the H2goesRail project – a joint initiative with German rail giant Deutsche Bahn – the train should begin providing a regular passenger service between Tübingen, Horb and Pforzheim, and replace a diesel train. The two companies will also showcase the H2goesRail project, as well as the Mireo Plus H, at this years' InnoTrans event in September in Berlin.  

In Steinbauer’s view, the key benefits of the Mireo Plus H is its ability to service non-electrified routes, replace diesel trains and deliver emissions-free train travel.

‘Only with a strong rail system and alternative types of drives will we be able to make a significant contribution to the fight against climate change. The Mireo Plus H enables climate-friendly and emission-free passenger transport,’ says Steinbauer.

‘With the Mireo Plus H, we’ve developed the next generation of hydrogen-powered trains that offers a particularly long operating range and faster acceleration. Each delivered train can save up to 41,000 tonnes of CO₂ over its service life of 30 years, compared to corresponding travel with cars,’ he adds.

After a joint roll-out event, the train will enter its commissioning phase at the Siemens Mobility test centre in Wildenrath, followed by what Steinbauer describes as ‘one year of homologation before it enters passenger service in January 2024.’

‘Especially in the fuel technology, we are expecting, on the one hand, economy of scale effects as quantities rise based on truck and bus businesses. On the other hand, the power density will be increased, as well as efficiency rates,’ he adds. 

‘Hydrogen can be produced through renewable means and therefore has the potential to be completely sustainable in a zero carbon world. Hydrogen trains share many of the same benefits to battery trains, but can achieve significantly greater range…’ - Stuart Hillmansen, University of Birmingham 

Equivalent performance

Another early pioneer in the development of hydrogen-powered trains is the smart mobility company Alstom, which has created the hydrogen fuel cell-powered Coradia iLint - based on the existing ‘service-proven’ Coradia Lint diesel train family. Described by the company as the world's first hydrogen train, the iLint is designed specifically for use on non-electrified lines and boasts a range of 1,000 km.  

A key advantage of the iLint is that its performance closely matches that of regular Coradia Lint diesel multiple units (DMUs), meaning they can operate the same timetable as current units, and use existing infrastructure without the need to invest in electrification.

Alstom has already made strong progress in rolling out the model across Europe and an initial two units have covered more than 180,000 km of regular passenger service over an 18-month period in Germany between 2018 and 2020. A total of 41 iLint models have also been sold across the country to replace a portion of the existing diesel fleet, and the first hydrogen series trains will be in regular service in Germany from this year.  

The company is also actively branching out with orders and trials across a range of other countries, including Poland, Italy Sweden, France, Austria and the Netherlands.

Hydrogen Locomotive Program

Elsewhere, Canadian rail company Canadian Pacific has recently been awarded a $15mn grant to 'dramatically expand' the scope of its pioneering Hydrogen Locomotive Program by increasing the number of hydrogen locomotive conversions in the project from one to three and adding hydrogen production and fuelling facilities.  

The grant, awarded under the auspices of the Emissions Reduction Alberta (ERA) Shovel Ready Challenge programme, matches an additional $15mn already earmarked by the company for the development project in 2021. The combined sum will be used to build upon early work on the design and construction of North America's first line-haul hydrogen fuel cell-electric powered locomotive – and expand the programme to convert an additional line-haul locomotive and a yard switcher locomotive.  

It will also enable the company to refine the process of converting three categories of diesel-electric locomotive powertrains to hydrogen-electric powertrains, which taken together represent the majority of locomotives in use throughout North America.

In addition to work on locomotive development, the ambitious scheme will also include the installation of hydrogen production and fuelling facilities at Canadian Pacific railyards in Calgary and Edmonton. The solar-powered Calgary facility will also feature an electrolysis plant to produce hydrogen from water.  

Meanwhile, the Edmonton site will include a small-scale steam methane reformation system to generate hydrogen from Alberta's abundant natural gas resources – and be designed to accommodate the possible future addition of greenhouse gas capture equipment.

Taken as a whole, the company claims the programme will create a global centre of excellence in hydrogen and freight rail systems in Alberta.

‘Our main goal was to produce a truly zero-emission locomotive and hydrogen allows us to do that. Hydrogen, being a portable fuel source, really fit the needs and showed that we could find an alternative to diesel locomotives,’ says Kyle Mulligan, Assistant Vice-President - Operations Technology at Canadian Pacific.

HydroFLEX

Another interesting initiative is the UK-based HydroFLEX project, a joint effort between the University of Birmingham and rolling stock company Porterbrook to develop a high-performance hydrogen train.  

As HydroFLEX project member Stuart Hillmansen, Associate Professor in Railway Traction Systems at the University of Birmingham, explains, the project was first conceived in 2018 at the Rail Live event, where the research team showcased a narrow-gauge hydrogen hero train. A full-scale mainline demonstrator model, based on a converted Porterbrook class 319 model, was subsequently revealed at Rail Live 2019, followed by mainline trials in 2020.

‘This was the very first time a hydrogen train operated on the British mainline. Since then, the train has been developed further and Porterbrook now have a fully functional high performance mainline train, which was showcased at COP 26. It is currently undergoing final testing at Long Marston, and will be ready for passenger service imminently,’ says Hillmansen.

The propulsion technology for the HydroFLEX is based on a bank of hydrogen tanks which store compressed hydrogen at 350 bar, before feeding it to PEM fuel cells that create DC electricity. The system also contains a lithium battery which works alongside the fuel cells to deliver DC power into the train. The trains’ existing traction system then converts this into the required voltage and current needed to drive the DC traction motors – with the fuel cells producing water as a waste product.

In Hillmansen’s view, the main benefit of the HydroFLEX is that it provides a means to power a train without using diesel, acts ‘very much like an electric train, and provides the same kind of service and passenger experience as a conventional electric train, but without the need for expensive electrification.’  

‘Hydrogen can be produced through renewable means and therefore has the potential to be completely sustainable in a zero-carbon world. Hydrogen trains share many of the same benefits to battery trains, but can achieve significantly greater range, and therefore are better suited to our network in the UK which has extended lengths of non-electrified tracks at the extremities of our network,’ he says.

‘Hopefully we will see HydroFLEX in regular passenger operation in the coming months as a trial and then the deployment of a small fleet. There are currently about 1,500 DMU trains in service and, ultimately, we need to find a viable alternative to running on diesels - and hydrogen is a strong contender for these vehicles,’ he adds.