The name of two stations:
eathrow Terminal 4 is a TfL Rail station serving London Heathrow Terminal 4 at London Heathrow Airport.
A separate Heathrow Terminal 4 Underground station caters for London Underground Piccadilly line services which is adjacent to this station. Transport for London Travelcards are not valid on Heathrow Express services, though it is for TfL Rail. Journeys to and from Heathrow Terminals 2 & 3 (Heathrow Central) are free of charge and can also be used by passengers changing terminals at Heathrow.