WX57 DSU This is one of the Emergency Response Units for use on the London Underground. It is a Mercedes Atego with John Dennis Coachbuilders bodywork. It is used to restore services after breakdowns and carries a range of equipment to do so. In the lockers are water pumps, jaws of life, airbags, chainsaws, generators, lighting and refreshments for the workers. It weighs 11 tonnes and cost £140,000. The 10 units are based at Acton, Camden, Vauxhall and Tottenham Hale.
Update: Since late 2009 various changes have been made to the location of these 10 vehicles. They are now at Camden (2), Acton (4), Battersea (2) and 2 training vehicles. Tottenham Hale base closed on 2nd September 2009 and Vauxhall also closed and was replaced by a new location at Battersea.