Heathrow Terminal 4 tube station

Heathrow Terminal 4 tube station stands in the London Borough of Hillingdon, on the Piccadilly line’s Heathrow branch. It sits on a unidirectional clockwise loop that leaves the main line after Hatton Cross and rejoins eastbound west of Terminals 2 & 3. The station has only one platform and is one of four on the London Underground with this arrangement. It is also the only one served by trains running in one direction only. A second station, Heathrow Terminal 4 railway, lies next to it for Elizabeth line services through the newer mainline tunnel. The loop tunnel and station were built between 1983 and 1985 by Balfour Beatty at a cost of £23 million. The Prince and Princess of Wales opened the station on 1 April 1986, though trains did not call until 12 April when Terminal 4 began handling flights. In 2005 the loop closed for two years while a new rail junction was built for Terminal 5. During this time passengers used a shuttle bus from Hatton Cross. The loop reopened in September 2006 with updated security and customer announcement systems. A visitor finds a single platform reached from a small ticket hall. Trains arrive from Hatton Cross and continue to Terminals 2 & 3 before returning. Alternate Piccadilly line trains serve the loop while others run direct to Terminals 2 & 3 and Terminal 5. London Buses routes stop outside, linking the station to the surrounding area. The loop’s unusual layout and the station’s history make it a notable point on the Underground network.