Passengers can expect disruption to Heathrow Express services from this weekend.
Due to Crossrail improvement works, a reduced service will operate over the next two months on Saturdays from April 2 until May 28.
The trains, which normally operate a 15-minute service between London Paddington and Heathrow’s Terminals 2 and 3 and Terminal 5 every 15 minutes, will depart every half hour on Saturdays.
Following a busy Easter weekend for Network Rail as it paved the way for the Crossrail programme in London, Berkshire and Essex, Network Rail announced its feasibility study for a Heathrow rail link to Waterloo would be 'very good value'.
The first service from London Paddington to Heathrow Terminal 5 will leave at 5.25am and then at 55 and 25 minutes past the hour until the final service at 11.25pm.
Departures from Heathrow Terminal 5 to London Paddington will see the first train leave at 5.27am and then at 57 and 27 minutes past the hour, with the last service at 11.42pm.
Trains between Heathrow Terminals 2 and 3 to London Paddington will operate from 5.33am and then at 03 and 33 minutes past the hour, with the last train at 11.46pm.
However, a normal full service departing every 15 minutes will run on three Saturdays: April 9, April 16 and May 21.
Heathrow Express has apologised for any inconvenience the changes to its regular schedule may cause.