Central line (London Underground) that the transport benefits of a Park Royal station on the Central line are not sufficiently high to justify the costs of construction. Central line (London Underground) The Central line is a London Underground line that runs through central London, from , Essex, in the north-east to and in the west. Coloured red on the Tube map, the line serves 49 stations over , which makes it the longest Tube line. It is also one of only two lines on the Underground network to cross the Greater London boundary, the other being the Metropolitan line. One of London's deep-level railways,
London Underground K Stock London Underground K Stock London Underground K Stock is a clerestory-roofed rail stock built for the District line in 1927. It was subsequently absorbed into the London Underground Q Stock. A complete review of District line rolling stock was carried out in 1926, leading to the withdrawal of further B Stock cars and their replacement, plus additional rolling stock to increase frequencies. This led to the construction of the K Stock, some of which was owned by the London, Midland and Scottish Railway (LMS). As built, the cars had hand-operated sliding doors. The doors were converted to air operation in