Programme update: Roxane McMeeken finds out where the £16bn Crossrail project is at

It will be the largest single addition to the London transport network for over 50 years – as long as it goes ahead. The £15.9bn mission to bore an east-west railway through London – some 118km of tracks – got under way in earnest this year, with completion due in 2017. Of course, the fear remains that the Tories might abandon the whole thing if they win next year’s general election, but the vocal support of London mayor Boris Johnson and the recent news that spending on the scheme will already have reached about £3bn by then are encouraging signs.

Rob Holden, chief executive of Crossrail, remains confident. He says:”The arguments for Crossrail are compelling: the UK needs better infrastructure and in particular better transport infrastructure. We have seen in the last 15 years or so the success of Thames Link, which links north and south London. We don’t have an equivalent west-east link, but Crossrail will do this.

“We acknowledge that any new government will review a project like this but we’re confident that when they do, they’ll back it.”

But what kinds of team is Holden looking to work with? Tellingly he wants to see “an awareness of the need to drive down costs”, including by simplifying designs. He adds that the headline £15.9bn cost is a maximum and he wants to spend far less: “£15.9bn cannot be the cost of the projects. I am not revealing the true amount I think we can do this project for because then contractors will think they can spend up to that amount rather than strain to keep costs down.”

That said, there is still work to be done – and work to be won – on the scheme. Here’s Building’s essential guide to the key contracts that have been signed so far and what is still up for grabs.