Refurbishment of D78 London Underground stock

Strukton Rolling Stock delivers traction and auxiliary systems to Vivarail for the refurbishment of D78 London Underground stock. The D78 stock is equipped with four new diesel engines for the power supply. Strukton Rolling Stock delivers two traction and auxiliary systems for each train, one in the front and one in the back of the vehicle. These systems convert the power to the right voltage for the motors, batteries and auxiliary systems.

IGBT technology

Strukton Rolling Stock’s systems are based on state-of-the-art IGBT technology, assuring smooth acceleration and higher travelling comfort for passengers. Each vehicle will be equipped with an IGBT chopper, which will provide for the required motor current. Strukton will integrate the traction system, control electronics and battery charger in one box. The technology is comparable with the system that Strukton Rolling Stock delivered for the Toulouse metro.

Pilot project

The conversion of the first vehicles is a pilot project for Vivarail. The pilot project has successfully passed all test in the summer of 2015 and the train runs on Vivarail's own test track. This will be followed by the conversion of up to 75 2- or 3-car units. A possible future option is storage of the braking energy in batteries or super capacitors, enabling the reuse of braking energy for the lighting and other on-board equipment.


While many railway vehicles are conversed from diesel-electric to electric, Vivarail is doing exactly the opposite, with the aim to have trains available for the local  lines serving regional centres in Great Britain. These lines are at present not electrified, and whilst electrification may be planned for the future, there is an urgent need for extra diesel trains  due to the massive growth in rail traffic which has taken place in recent years.

75 ‘new’ trains

Vivarail was especially set up for the refurbishment and upgrading of D78 stock purchased from London Underground. This stock first entered service in 1980, but the Vivarail conversion will effectively produce new trains. A new propulsion system, new control equipment,  new cab structure and new interiors will result in trains to the latest stand, with a up to 75 new trains that can be leased or bought.

BBC about the refurbishment of former D78 London Underground stock

Video of the Vivarail train