London’s £15bn Crossrail project is to open nine months after its scheduled launch to allow more time for testing.
Europe's biggest infrastructure project will help ease London's chronic congestion by connecting major landmarks such as Heathrow Airport and the Canary Wharf business district.
The route, to be known as the Elizabeth line, had been due to open in December, but will now be launched in autumn 2019 "to ensure a safe and reliable railway", transport officials said.
When fully operational, trains will run from Reading and Heathrow in the west through 13 miles of new tunnels to Shenfield and Abbey Wood in the east.
It will operate as three separate services - as previously planned.
Crossrail says the new line will connect Paddington to Canary Wharf in 17 minutes.
When fully operational, trains will run from Reading and Heathrow in the west through 13 miles of new tunnels to Shenfield and Abbey Wood in the east.
It will operate as three separate services - as previously planned.
Crossrail says the new line will connect Paddington to Canary Wharf in 17 minutes.
An estimated 200m passengers will use the new undergound line annually, increasing central London rail capacity by 10% - the largest increase since World War Two.
Crossrail Limited described the 10-year project as "hugely complex".
It said "further time" was required for testing, and that contractors needed to complete work in the central tunnels and to develop "railways systems software".
Transport for London (TfL) said more time was needed "to ensure a safe and reliable railway for customers from day one of passenger service".