stock were built in 1962–63 to replace the F and P stock trains on the Uxbridge service. These were arranged as 4-car units which could operate as four or eight car trains. Four car units operated on the Chesham shuttle and, from 1977, on the East London line. The transfer of CO/CP Stock from the Metropolitan to the District line in the early 1960s allowed some of the Q stock to be scrapped. In 1968, an order was placed for 35 six car trains to replace the CO/CP Stock on the Hammersmith & City and Circle lines. These were arranged as two units with a driving cab in the motor car at one end only and normally run as three pairs. These trains were designated C69 stock. The remaining CO/CP and R Stock on the District line were replaced in the late 1970s by new trains. A shorter train was needed on the Edgware Road branch due to the platform lengths so more of the C stock units. The rest of the District line could use longer trains and new D Stock trains were introduced between 1979 and 1983. A new Fire Safety Code of Practice, drawn up following the King's Cross fire in November 1987, lead to internal refurbishment of trains that included replacing the interior panelling and fitting or improving the public address systems. At the same time the exterior of the trains were painted as it had proved difficult to remove graffiti from unpainted aluminium. The first refurbished trains were presented to the media in September 1989, and the project launched in July 1991. the Metropolitan, District, Circle and Hammersmith & City lines are being upgraded, with new air-conditioned S Stock in use. Also, the sub-surface track, electrical supply and signalling systems are being upgraded in a programme designed to increase peak-hour capacity by the end of 2018. A single control room for the sub-surface network is to be established in Hammersmith and an automatic train control (ATC) system will replace signalling equipment installed from the 1940s. Tube electric multiple units Early trains The first tube railway, the City and South London Railway, opened in 1890 with electric locomotives hauling carriages. In 1898, the Waterloo and City Railway opened to the public using electric multiple units. Each four-car train had two trailers and two motor-cars with two motors that could be directly controlled from either car. A