A “significant” risk exists that infrastructure being built under the £5.5bn Thameslink project will not be compatible with the trains procured for the upgraded line, the government’s spending watchdog has warned.
The National Audit Office said delays in buying new trains for the line, which runs through central London, meant work may be needed to adjust new infrastructure to accommodate them.
Its report, “Progress in the Thameslink programme”, warned that the award of the PFI contract to design, build, finance and maintain the trains was more than three years late.
“Delay in signing the contract adds logistical complexity to delivery of the infrastructure project, as more detailed design assumptions have to be made about the interface between the infrastructure and the new trains,” said the spending watchdog.
“The technical interfaces should be clearly defined in the terms of the contract to buy new trains when it is signed. However, the Department for Transport’s systems integration team and Network Rail have identified that there remains a residual and significant risk of changes to infrastructure being required to resolve issues resulting from the train design.”
The NAO said the first phase of the Thameslink programme, which aims to boost passenger capacity by 50%, was completed on time and under budget in 2011.
But the report added that completion of the second and final phase had been delayed from 2015 to 2018 – and that it was unclear whether even this revised ambition was realistic.
“The Department has not yet fully mapped out the critical path of this programme as a whole based on a revised timetable for the delivery of new trains to determine whether 2018 is still feasible,” it said.
Civil Engineering Contractors Association director of external affairs Alasdair Reisner backed the building of infrastructure ahead of the train deal being signed.
“The sooner there is clarity over the trains contract, the better,” he told NCE. “But it is good to see [the trains deal delays] did not slam the brakes on the whole project.
“There may be some additional costs to deal with but these will be far outweighed by the benefits of an infrastructure project increasing capacity at some of London’s busiest stations.”
Network Rail said it remained committed to its construction plan.
A spokesman said: “The issue of residual risk refers to the introduction of new trains onto new infrastructure, which is an important aspect of the Thameslink Programme.
“Because the central core of Thameslink will be operated using cab signalling and automatic train operation, it means the trains are more closely linked to the infrastructure.
“However, we have a testing programme in place to learn as much about the equipment as we can before introducing the trains to the live railway.”
£40M for London transport schemes
London mayor Boris Johnson has secured £40M of government funding for transport schemes across the capital.
The money, part of a £111M pot secured from the Government’s Growing Places fund, includes £25M for an upgrade of rail services in the Upper Lea Valley area of the city.
The upgrade of the West Anglia route between Angel Road Station and Stratford will see Lea Bridge station reopened and Angel Road given a £2.5M facelift.
The Lea Valley scheme is part of a wider £72M upgrade of the West Anglia route which includes £44M of funding from Network Rail.