FOUR custom-designed battery locos have been built by Clayton Equipment for use by London Underground PPP contractor Metronet in a five-month modernisation programme for the Waterloo & City Line which begins this month (p178).

Designed to suit the restricted loading gauge, sharp curves and steep gradients of the 2·37 km tube line, the 15 tonne locos have two 75hp motors, with IGBT solid-state controls, spring-applied pneumatically-released disc brakes and a camera to aid shunting.

Proven components have been used for the locos, but the frames are to a bespoke off-centre design, matching custom-designed wagons to provide staff with an escape route down the side of the trains.