The introduction of Elizabeth Line trains on Crossrail’s Heathrow branch has been delayed by signalling problems as the £14.8bn project nears completion.
The new trains were expected to be rolled out on the branch connecting Paddington and Heathrow from May, but delays to the testing of the signalling system in the Heathrow tunnel and onboard the trains have pushed the date back to later this year.
The existing two-trains-per-hour service pattern will continue, using the old Heathrow Connect trains, until supplier Bombardier has finished testing.
Transport for London (TfL) said it expects to increase Elizabeth Line services between the central London station and the airport to four trains per hour later this year.
Transport for London’s Elizabeth Line operations director Howard Smith said: “Our supplier Bombardier continues to test the Elizabeth line trains and the new signalling system in the Heathrow tunnel.
“While this takes place, we will operate the same service pattern (two trains per hour) to Heathrow as exists now, using the existing Heathrow Connect trains.
“We will also run two trains per hour between Paddington and Hayes & Harlington, which is the same frequency as now, using the new Elizabeth line trains.
“Once Bombardier has completed testing we will increase the frequency to Heathrow to four trains per hour later this year.”
Crossrail Ltd developed a “revised delivery schedule” to save the December 2018 opening date of the central section between Paddington and Abbey Wood from being pushed back after suffering design flaws and testing problems.
When the full line opens in December next year trains will run from Reading and Heathrow in the west, through 42km of new tunnels under London, to Shenfield and Abbey Wood in the east.