A senior source on London’s Crossrail project has told the BBC that the metro line could be delayed until spring 2021, pushing costs above the present estimate of $17.6bn.
The 118km line, which will link Shenfield in Essex with Heathrow airport and Reading, was to have opened at the end of last year. The physical infrastructure has been built and the delivery team is testing the line’s signalling systems. However, this "dynamic testing" phase is "proving more difficult than was first thought", according to the BBC’s unnamed source.
Once dynamic testing is complete, the final phase will be a kind of dress rehearsal, in which the entire system is operated without passengers.
The source said the best case scenario would be an opening in spring 2020 and the worst case a year after that.
Many of the stations along the line are incomplete, with Paddington (pictured) and Bond Street the furthest behind, but the main problems being encountered are in configuring Siemens’ signalling software to work with Bombardier’s trains.
The possibility of a delay to 2021 was also flagged in a report by the House of Commons’ Public Accounts Committee, published earlier this month.
This said: "Until a revised opening schedule has been agreed, we are not convinced that new services will start to run in 2020 as now hoped, nor that the additional £2.8bn of funding provided will be enough."
The report criticised both the Department of Transport and Crossrail Limited, which is Transport for London’s delivery agency, for being unable to fully explain how the programme had been "allowed to unravel" or to "properly report the position of the programme and its risks".
It added "We are becoming increasingly alarmed at the continual shortcomings our work has highlighted in the Department’s project management and oversight of the railways and we will continue to look closely at progress with this programme."
The BBC suggests that the political importance of the scheme led to a culture where staff were reluctant to be the bearers of bad news.
The committee’s report notes that when one of its representatives visited a site in June 2018, they were told that the programme was on track.
"It was not until August 2018, four months before the central section was due to open, that there was any public recognition of the seriousness of the problems with the programme. Since then, it has become clear that the programme will be delayed by at least a year and forecast costs have potentially grown by nearly a fifth.
"There is an incongruity between how the programme can be described as performing so well and such significant issues emerging so quickly."
Image: Crossrail’s rendering of Paddington Station