HS2 admits it got its numbers wrong as Birmingham train depot let at more than three times original £250m budget

HS2 has admitted it got its numbers wrong for what a new train depot and control centre on the outskirts of Birmingham would cost with the job at Washwood Heath now set to be £856m – more than three times its original budget.

The job has finally been let to a joint venture of Taylor Woodrow and Aureos – the renamed civils business that Keltbray sold two years ago – more than six years after it was first advertised.

At the time a PIN notice for the job appeared in January 2020, it carried an original price tag of £247m meaning the final price has now gone up by 247%.

Procurement has repeatedly been delayed while the cost quickly increased to £275m within a year of being advertised, with the last reported figure being £480m.

In a statement to Building, HS2 admitted that mistakes and been made estimating the scale of the job – which has also been hit by the price inflation that has affected construction over the past few years.

A spokesperson for HS2 Ltd said: “Our chief executive, Mark Wild, has been clear that mistakes were made during the early stages of the HS2 project, particularly in terms of estimating costs and the amount of time needed to complete the project. It is now clear that we set an unrealistic initial cost estimate for the depot and control centre.

“This mismatch became clear during the procurement process and we began a series of fresh benchmarking exercises to fully understand the potential costs associated with the design.

“This included both internal benchmarking exercises within HS2 Ltd, and an independent benchmarking study commissioned by the DfT, comparing the estimated cost of Washwood Heath to similar depot projects elsewhere in Europe.”

HS2 said that Wild and the independent review panel ran the rule over the figures assessing the contract’s “readiness to proceed and contract management capability” with the railway adding that it “reflected the lessons learned from the Main Works Civils contracts, James Stewart’s review of HS2 governance, and Crossrail [where Wild was brought in as chief executive in 2018]”.

Turkish contractor Gülermak was the surprise name on the original three-strong shortlist but dropped out of the running in 2023 to leave a pairing of Taylor Woodrow and Aureos up against a team featuring VolkerFitzpatrick and VolkerRail.

Designed by local architect Glenn Howells, the centre is expected to employ more than 550 people.

The 30ha scheme was given the green light by the city council at the start of 2024 with the depot including a rolling stock maintenance building, carriage wash, automatic vehicle inspection building and sidings where trains can be stored overnight.

Also on the same site will be the Network Integrated Control Centre, where staff will manage the dispatch of trains, communicate with drivers and ensure that services run smoothly.

Separate buildings will house offices and facilities for cleaners and drivers. The remaining area will be released for commercial development and used to create new green spaces and wildlife habitat.

A team from HS2’s enabling works contractor LM, a pairing of Laing O’Rourke and Murphy, completed the demolition of the buildings on the site in 2020. The Washwood Heath complex was formerly home to the Metro-Cammell railway works, which closed in 2004.

Meanwhile, the reset of the project promised by the government is still slated to be made by the summer despite reports it had been pushed back.

In March, transport secretary Heidi Alexander said Wild will come back to Parliament by the summer recess, scheduled for the middle of July, with his revised cost estimate and schedule of when the railway will be completed.

Building understands this timetable has not shifted with the government announcing in its last update on the scheme that more than £43bn has been spent on building HS2 so far – up from the £37.6bn announced last July.