Every day, thousands of passengers travelling southwest on trains leaving Aldershot station pass a cluster of solar panels beside the tracks. Many may not notice the installation, but the train they are on is drawing power from it.
“On a sunny afternoon, if you are catching a train through Aldershot, a little bit of the energy for that train will come from those solar panels,” says Leo Murray, co-founder and chief executive of Riding Sunbeams, a start-up aiming to use renewable energy resources for rail electrification projects.
Riding Sunbeams built the Aldershot array in 2019. It is small in scale at just 40 kilowatts, equivalent to roughly ten typical British household rooftop systems. But it demonstrates how renewables can feed directly into the railways.
Mr Murray says it is currently the only solar array in the country that delivers power directly to rail to move trains. “If you are a railway, this is the cheapest electricity you can buy,” he says.
Around the world, many trains still run on diesel. To go electric, rail operators have traditionally relied on electrified rail or overhead lines with pantographs on the train roofs. Installing either system can be expensive and technically demanding.
Engineers are developing new ways of implementing such systems, and alternative approaches are also emerging that could speed up electrification.
A major barrier is often the capacity of the local electricity grid. “It is hard to get access to a large enough connection for powering your trains. That problem has only become much worse,” says Mr Murray.
This is why he sees solar panels as valuable in enabling railway electrification projects.
After the Aldershot project, Mr Murray hoped Riding Sunbeams would move on to build a full-scale commercial pilot, but funding challenges slowed progress.
Now, Network Rail is seeking suppliers for rail-side renewable energy projects.
“This is the big one,” says Mr Murray, noting that his company plans to bid.
New projects add complexities. At Aldershot, the track was already electrified, so the solar panels were connected to an existing system. For diesel-to-electric overhead line transitions, using solar is harder because solar panels produce direct current electricity while overhead lines use alternating current.
Work is underway in England to develop a converter that could resolve this.
Meanwhile, Colton Junction between Leeds and York, the fastest railway junction in the UK where trains pass at up to 125 miles per hour, was recently electrified with the help of software developed at the University of Huddersfield. The software creates a 3D model of the overhead line system, allowing engineers to plan construction in detail, reducing costs by cutting out some traditional testing.
“Everything was specified in the software in terms of measurements,” says João Pombo, associate director at the university’s Institute of Railway Research. “All the trains have been running at maximum speed at that junction since August.”
In Poland, start-up Nevomo has developed an electromagnetic propulsion system. A thick aluminium cable is fitted between the rails to generate a magnetic field strong enough to move freight wagons fitted with magnets.
“We eliminate locomotives completely,” says founder and chief executive Ben Paczek. “Each wagon becomes independent. They can also operate in groups.”
The ability to stop and control wagons more precisely means many could be run close together on a single track, increasing capacity. Nevomo expects small-scale installations at a steel plant in Bremen, Germany, and a port in India next year.
In the United States, Parallel Systems is developing battery-powered freight wagons that move independently across rail networks. The company says the wagons would operate like packets in a distribution system rather than traditional long-haul freight trains. “If we simply grab 10 percent of the trucking market, we have doubled the rail industry,” says co-founder and chief executive Matt Soule.
Stuart Hillmansen at the University of Birmingham, who has worked with Riding Sunbeams, says coordinating independently moving wagons could be challenging on existing rail networks. He says the key is proving the economic value of new systems.
“All of these technologies are physically feasible and can work. The challenge is making the business case,” he says.
