of the Jubilee line, diesel-powered locomotives manufactured by Schöma of Germany in 1996 took over some of the duties of the battery locomotives. Metronet battery locomotives In February 2006, Metronet received four small battery locomotives. These were named Walter, Lou, Anne, and Kitty, names that pun the name of the line they were bought to work on, London Underground's Waterloo & City line. They are used for hauling materials and equipment and were specially designed and built for work in narrow tunnels with tight curves and steep gradients. Clayton Equipment of Derby designed and built them in about four months. The locomotives weigh 15 tonnes each and have 200 Volt DC motors providing to each axle. As a fail-safe feature they have spring-applied disc brakes that are automatically applied if something goes wrong. Built-in cameras are connected to screens in the cab to make shunting easier. Unlike the earlier battery-electric locomotives, these locomotives cannot draw power from the electrified rails. Under normal use this is not a problem because they are designed to work on engineering projects in tunnels where the power is cut off anyway, but it does mean they have to return to the depot to be recharged. References Notes Bibliography Battery-electric Standard gauge locomotives of Great Britain Battery electric locomotives