Pre-Covid, there were almost 300 million journeys a year on Britain’s light rail systems. Their high capacity provides urban connectivity that drives economic growth. For example, the Docklands Light Railway helped regenerate London’s Docklands whilst Manchester’s Metrolink was the catalyst for Salford’s Media City. Unlike buses, trams attract motorists from their cars and so reduce congestion and emissions.
Yet Britain has only nine light rail systems compared with 28 in France and 57 in Germany. In Europe, towns with populations less than 50,000 can support a tram system, whilst Leeds – with a population of 800,000 – has the distinction of being Europe’s largest city without one. Over the last 70 years, Britain has invested 40% less on transport than the rest of Europe. With increasing recognition of the need to reduce urban car use, more light rail systems are required. Yet conventional tram systems typically cost around £50 million per kilometre, with a 1.7km extension of a Birmingham tram line costing £160 million. At these prices, providing a number of medium-sized cities with a light rail network is quite simply unaffordable.
However, in 2017, one such city, Coventry (population 320,000), decided that it should be able to afford a suitably specified light rail system as part of its transport strategy when the City Council approved a plan to develop a Very Light Rail (VLR) network. One reason for this decision is that the city has significant exceedances of air pollution limits and light rail does not have the non-tailpipe emissions from brake pads and tyres that buses have.
Since then, the City Council has been working with the University of Warwick’s WMG (Warwick Manufacturing Group) to develop a VLR system at a target cost of £10 million per kilometre.
Innovative track and vehicle
To achieve this target cost, a shuttle-type vehicle has been adopted which uses lightweighting techniques developed by WMG, has no overhead catenary, requires minimal utility diversions and reduces the earthworks required. WMG has partnered with Transport Design International to design the prototype vehicle which is being built by NP Aerospace in Coventry and is now almost complete. This prototype is self-powered from a 750V 54kWh battery that gives a range of 70km. An out and back journey will consume about 9kWh. The intention is that the battery can be charged overnight from a 20kW supply and during the day receive 3.5-minute rapid charging from a 200kW supply. Packaged underfloor is the electronics and the lithium titanate battery which has a safe chemistry.
The vehicle is made from steel, aluminium and composites, with a carbon/polyethylene bumper and carbon/Kevlar cab ends. Polycarbonate windows meet the requirements of the post-Croydon accident recommendations. It has a maximum speed of 70kph and can tackle a 5% gradient. All axles are driven and an innovative bogie enables the network to have 15-metre radius curves. A future vision is autonomous driving which would significantly reduce operational costs and offer a greater load factor.
The production vehicles weigh 11 tonnes, are expected to cost around £750,000 each and normally carry 50 passengers or 70 in crush conditions when their weight will be 16.5 tonnes, giving them a maximum four-tonne axle weight.