Tube frame for Coventry's Very Light Rail 'so light people can pick it up'

A new train chassis made of carbon fibre tubes is so incredibly light that people can “pick it up” to get a sense of how it will work in practice, a manufacturer has claimed.

The Very Light Rail vehicle frame from WMG at the University of Warwick and partners is formed of carbon fibre composite tubes, held together with adhesive and simple welding. The demonstrator is “an eye-opener for industry players who can see it, touch it and even pick it up,” said Lyndon Sanders, director of component manufacturer Far.

The technology is being developed for the Coventry Very Light Rail project, a low-cost tram-like system that will run on rails and roads. Trams typically cost more than £80m per km, but the WMG is aiming for less than £10m per km with partners Far and Transport Design International.

“The aim is to revolutionise the sector and open up cities the size of Coventry with something to replace a tram system,” said engineer and WMG associate professor Dr Darren Hughes to Professional Engineering.

The demonstrator includes an underlying tubular ‘spaceframe’ chassis which provides the body shell. The beams have a consistent external diameter but tailored wall thickness to give optimum performance depending on where they are used. This reportedly keeps tooling costs low and allows for all the joining to be standardised.

‘Significant cost benefits’

The WMG is taking advantage of years of experience with automotive manufacturers such as Jaguar Land Rover to develop the Very Light Rail vehicle, said Dr Hughes.

“We are essentially transferring that low-cost technology from the automotive industry to rail, but only using it where it is applicable,” he said. “It can be used when replacing bus or tram services, giving significant cost benefits.”

Other potential advantages include carrying more passengers while reducing energy required for movement and weight stress on rails and the road, a predicted long service life and easy repairs.

Crossing the tracks?

The vehicles are “definitely not” designed to be compatible with mainline trains, said Dr Hughes. A lightweight chassis could sustain serious damage in any crash with a heavier mainline train. Instead, he said the project is aiming for the “niche” of vehicles that do not interact with the mainline.

Technology could nonetheless be transferred from the Very Light Rail to mainline rolling stock, where applicable. Lightweighting is not always relevant for rail as higher mass can aid adhesion to the rail, said Rail Engineer editor and Scottish IMechE railway division secretary David Shirres. “Being absolutely lightweight is not advantageous in some situations. It is really about what’s appropriate.”

Future flexibility

Previous announcements included details of the vehicle’s application in Coventry. It will reportedly hold 50 people and use battery power to negate the need for overhead lines, as well as providing flexibility for future routes. Developers hope it will eventually be autonomous, and are aiming for first rail testing by 2020.