Central line

The Central line was a stretch of railway on the London Underground. (TV: The Web of Fear) It was coloured orange on the London Underground map. Stations on the Central line included Tottenham Court Road, Holborn Kingsway, Chancery Lane, (PROSE: "London Underground") St. Paul's, (TV: The Web of Fear, PROSE: "London Underground") Bank and Liverpool Street. (PROSE: "London Underground")

St. Paul's was a station on the line. During the Yeti invasion — also called the "London Event" — Jamie McCrimmon and Gwynfor Evans managed to break free of the Circle line onto the Central just before the Yeti completed their Web around the Circle line. (TV: The Web of Fear)

When on Earth many tens of thousands of years later, after the planet had been ravaged by solar flares and all of London was buried, the Fourth Doctor found a subsidence which he postulated might lead to the remnants of the Central line. (TV: The Sontaran Experiment)

Behind the scenes
Central Line is shown to be orange on the map in "London Underground". This matches the real world colour from the official map of the early 1960s. Today, however, the Central Line is shown in red on the official map of the London Underground.