The official countdown to the Olympic games, which started a few days ago, coincided with the countdown to completion of another much-anticipated project in the British capital: the large-scale transformation of the Kings Cross Station by John McAslan + Partners - steadily reaching its next phase of completion.

The western concourse, with its adjoined facilities and the station's western range of buildings, is set to open in spring 2012. At the construction site, things have slowly been taking shape. Works on the existing platforms 1-8 - finishing this winter - are to be closely followed by a new pub, office space, passenger lounges and facilities that will accompany the new concourse.

A big part of the work was the meticulous restoration of the original Victorian buildings that made up the complex - the beautiful old Parcels Building for example, long in disuse, will now be restored to its former glory and converted into a pub. 'People often underestimate the difficulty of working with a grade II listed building', says architect John McAslan. 'It's a bit like archaeology really.'

The new concourse's roof is no doubt going to be a show-stealing feature. Created by McAslan's team together with the valuable engineering expertise of

Arup, it's an impressive white shell-shaped vaulted structure, almost twice the size of the British Museum Great Court's roof. The semi-circular shape that has been used covers the space neatly in one clean sweep, while the mesh's funnel-shaped base solution sorted all of the design's structural problems by leading all the forces into the ground.

Used as an entrance way to the station, the old main entrance on the west side has been reinstated as a key circulation point, while the current south entrance will be the main exit for the station, leading to the new open square by Stanton Williams. Inside, the much-discussed glass bridge for movement across platforms is now almost ready for the final opening before the Olympic games, while product and signposting is going to be cleverly incorporated in the design for a neater interior, and the main train shed will feature photovoltaic panels on its glazed roof.

With the overall works - the square included - scheduled for completion in autumn 2013, the architects and engineers still have a little way to go. However, the project is confidently moving forward despite its several challenges, some of which the team seem especially proud to have overcome. 'It is key that the station remain completely operational throughout the construction, which is amazing for a project of this size,' says Arup's Director for Kings Cross Station John Turzynski.