Rechargeable train to run on GB rail network ‘this summer’
Vivarail, the company giving a new lease of life to former London Underground trains, intends to run its first production battery-powered unit on the national railway network this summer, with full approval for passenger service.
The two-car train has four banks of lithium-ion batteries - two under each vehicle - with a combined capacity of 106kWh. It requires an eight-minute charge at each end of the journey, but with a 10-minute charge the range is extended to 50 miles (80km). This is expected to increase as battery technology develops.
The train can be charged through existing infrastructure - overhead line or third rail - and for non-electrified lines Vivarail has developed a static battery bank as an alternative.
The charging system is fully automated. As Vivarail describes it: “The train simply stops at the stop board and connects to the power source without the need for human intervention. The rate of charge is identified by the on-board power electronics and once the charge time is complete or the system detects the driver selecting power, the system then shuts down before the train pulls away.”
The charging point needs an electrical supply of 11kV or 33kV, but if the supply is not strong enough a static battery bank can be used to provide an energy reserve, charging overnight and discharging to the trains through the day. This method takes advantage of lower overnight electricity tariffs. While novel for the rail industry, a similar technique is already used in other applications, such as for electric car charging at motorway service areas.
Vivarail’s business is based on re-engineering and completely refitting former D-Stock trains from London’s District Line for use on the national network. With their aluminium bodies these trains are still in good condition and expected to have a useful lifespan on lines where there is no requirement for high speeds. A modular concept means that traction power can be provided by diesel gensets or battery packs, either of which will fit into the same space envelope under the body for connection to the train’s electronic systems.
In December, West Midland Trains confirmed that it would use diesel versions of the trains on the Marston Vale line between Bedford and Bletchley from December 2018, subject to satisfactory testing.
A prototype diesel unit was severely damaged when it caught fire during a test run in December 2016, so the firm is keen to stress the safety of its new battery version. According to the company statement: “The lithium ion batteries on our trains work only within defined temperature parameters and performance is constantly monitored, so should an incident occur it can be quickly contained and the gases will be filtered before being allowed to dissipate naturally.”
With the prospect of hydrogen trains in the news at the moment, the company has confirmed that it is investigating the possibility of using fuel cells to replace or supplement the batteries “and foresee our trains will be running with hydrogen power in the next few years”.