Heathrow Connect was an operating company jointly run by Heathrow Express and Great Western Railway until May 2018. The service ran between Heathrow Airport and London Paddington; the same route as the Heathrow Express but included several West London stations en route.
Transport for London took over the services and plans to incorporate them into a new Elizabeth Line, due to be launched in 2021.
Heathrow Connect Train Map
If you’re looking to travel abroad, Heathrow Airport is an excellent place from which to fly. While the Heathrow Connect services no longer operate, the Heathrow Express offers a direct route to the airport from London Paddington.
The Heathrow Express does not include intermediate stations in West London; these will be on offer as part of the new Elizabeth Line.
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Source: Heathrow Connect Network Map