London Underground D78 Stock total of five 3-car sets, to be built as BMMUs, in June 2018. London Underground D78 Stock The London Underground D78 Stock, commonly referred to as D Stock, was a type of sub-surface rolling stock which operated on the District line of the London Underground, except on the Wimbledon to Edgware Road service. Following the withdrawal of the C Stock in June 2014, these were the oldest subsurface trains in service on the London Underground. The first units were withdrawn in January 2015 with the last withdrawn on 21 April 2017. The D stock was ordered in 1976 to replace
London Underground Electronic ticketing in the form of the contactless Oyster card was introduced in 2003. London Underground services on the East London line ceased in 2007 so that it could be extended and converted to London Overground operation, and in December 2009 the Circle line changed from serving a closed loop around the centre of London to a spiral also serving Hammersmith. Since September 2014, passengers have been able to use contactless cards on the Tube. Their use has grown very quickly and now over a million contactless transactions are made on the Underground every day. The Underground serves 270 stations.