After years of work, one of the most complicated stations on London's troubled Crossrail project has finished at more than $1 billion, seven times the original budget. Carrying platforms for the new Elizabeth rail line, Whitechapel station in east London was remodeled from Victorian-era structures while trains continued running on existing London Underground and Overground services.

"The whole team at Whitechapel have done a fantastic job weaving between the existing operational transport services," says Mark Wild, CEO of the project company Crossrail Ltd. Steve O’Sullivan, project director of construction joint venture BBMV, which includes Balfour Beatty Construction Ltd., Morgan Sindall plc. and Vinci Construction, describes the project as an "incredible feat of engineering."

The concourse was built on 2,800 tonnes of structural steelwork straddling two operational railway lines.

Awarded to BBMV with a target price of $151 million in 2010, the cost of the Whitechapel design-build contract rose to $1.1 billion by March, according to the National Audit Office. The hike was among the biggest on the Crossrail program, which has increased overall about 30% above the 2010 budget to $24.6 billion.

While civil construction ran smoothly, nobody involved "appreciated how complex it would be to bring together all of the separate systems and assets required and assure them as safe and working, or how long it would take," say the auditors.

Linking communities east and west of London with 42 km of tunnels and ten new stations, the line was originally due to open in December 2019. Full services are now scheduled for the first half of next year.

“There are now encouraging signs that Crossrail is in a more stable position," Gareth Davies, audit office head, stated recently. "However, it will require further funding to complete, and there are still significant risks that must be managed as the Elizabeth line undergoes operational testing."