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FEATURE: Solar trains, modern steam – could these 5 projects transform UK rail?

Joseph Flaig

Stock image (Credit: Shutterstock)
Stock image (Credit: Shutterstock)

Belching huge plumes of smoke and breaking the peace with pounding pistons and shrill whistles, steam trains were a potent symbol of the Industrial Revolution’s energy, dynamism – and pollution.

Two centuries after their invention, rail travel is now rightfully seen as a sustainable method of transport and freight, thanks to the sheer number of people and goods it can take out of cars and lorries.

Many trains in the UK still run on diesel however, with almost a third using the fossil fuel as their only source of energy. To cut emissions, the government announced last year that it would remove all diesel-only trains from the network by 2040.

Now, it has announced five “innovative schemes” to cut carbon emissions from rail will receive £350,000 as part of the Department for Transport’s First of a Kind competition. But with experts repeatedly urging the government to go full steam ahead with electrification, is the £1.75m fund money well spent or simply delaying the inevitable?

­Riding on sunshine

Electrification is frequently touted as the simplest and most realistic decarbonisation method for the rail network ­– but then, the cynics say, why electrify if the electricity is generated using fossil fuels in the first place? Riding Sunbeams aims to cut out the middleman and ensure renewable energy powers trains.

The company hopes to tap what it calls “Britain’s favourite energy source” by installing solar panels along rail corridors and on south-facing embankments, transferring the Sun’s energy through power exchanges, converters and substations to directly power trains. Storage cabinets with 15-battery modules could also store electricity to tackle the issue of intermittency.  

The concept is a good idea, says David Shirres, editor of Rail Engineer, to Professional Engineering. He says, however, that it would only be suitable for DC third rail electrification, as 25kV AC electrification needs high voltage substations.

A report by 10:10 Climate Action and imperial College London, the collaborators behind the project, says there are “major opportunities” to use solar traction power on DC electrified lines on the London Underground, Merseyrail in Liverpool and on the Kent, Sussex and Wessex commuter rail networks. Solar farms would only provide about 10% of the power required by trains each year, however. 

Steam, but not as you know it…

Burning vast amounts of coal, wood or oil, traditional steam locomotives are hardly environmentally friendly. Steamology Motion hopes to give steam a modern makeover with its W2W Zero Emissions Power System, a range extender for Vivarail Class 320 rolling stock.

The team includes director Jeremy Bliss, a developer on the land speed record-breaking Thrust SSC project, and they hope to carry technology across from the famous car to the rail sector.  

Few details are available, but the project aims to boost air quality at stations and reduce noise and pollution. W2W stands for water-to-water, and the system has a compact energy dense steam generator at its heart. “Steam is generated using energy stored as compressed hydrogen and oxygen gas in tanks,” the project summary says. “High pressure, superheated steam is used to drive a turbine to do useful work by generating electricity.”

It adds: “Renewable energy is used to power electrolysis to generate the hydrogen and oxygen gas and to compress the gas into storage tanks. This W2W closed cycle is emission-free, producing no carbon or NOX emissions in a repeatable cycle without charging losses.”

This is exhausting

Like Steamology Motion, Vortex Developments aims to transfer automotive technology to rail. The company promises a “game-changing” exhaust design that produces volumetric efficiency of combustion in engine cylinders and reduces fuel consumption – also reducing the carbon footprint and diesel particulates by more than half.

The firm will run an eight-month project developing a vortex exhaust for Class 66 freight engines from 1 March, following the development of the technology for passenger Class 156 trains. Those devices achieved a 13.2% mean reduction in diesel use compared to standard exhausts.

Although it will be developed in the UK with government funding, the first customer to use the vortex exhaust could be Deutsche Bahn.

Heavy duty after-treatment

Porterbrook is also focusing on the exhaust to reduce the emissions from its diesel-powered rolling stock. The company will transfer an Eminox after-treatment system already used on heavy-duty vehicles such as buses to trains, starting with a Class 158 diesel multiple unit in normal passenger service. 

“Rail-specific challenges, such as high exhaust temperature duty cycles, will be overcome as part of the project, utilising advanced catalyst technology,” the company says in its project summary. “State of the art telemetry will be fitted as standard to provide real-time onboard diagnostics and abatement performance data from the system.”

Pump it up

The fifth project awarded £350,000 is from Unipart Rail. The firm hopes to use a commercial version of a digital displacement pump and electronic controller, instead of a traditional hydraulic pump with a swashplate. The technology’s high efficiency could “significantly” reduce fuel consumption.


Rail minister Andrew Jones hailed the concepts as “fantastic projects” that will help decarbonisation progress before 2040.

“All would seem to have worthwhile initiatives to decarbonise self powered vehicles,” said David Shirres to Professional Engineering. “However, for me the key issue is that initiatives to produce power for electrification from renewables, or to reduce cost of electrification, would produce greater carbon savings.”


Content published by Professional Engineering does not necessarily reflect the views of the Institution of Mechanical Engineers.
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