Christmas engineering complete

A 350-tonne, 22-metre, concrete and steel section of railway bridge was successfully slid into place over Christmas at Blackfriars, paving the way for the station’s continued reconstruction.

Before: The bridge complete and ready to slide in

After: The bridge is in place and waiting for track and signalling

The existing bridge section was carefully dismantled and removed from its position between platforms four and five at the north of the station by an 800-tonne mobile crane.

The new section of bridge was specially designed and built on six metre high trestle towers in a site compound to the east of the site, to keep the station open for as long as possible and to minimise impact on passengers.

Two hydraulic rams then pushed into place the new section of bridge from the east side site compound before signalling, communications cables, track and ballast were all reinstated.

The strengthened bridge means Network Rail can later reroute the railway tracks at Blackfriars to run down the east side of the station. That will allow its contractors to press ahead rebuilding the west side.

This major piece of civil engineering was part of almost £10 million of work carried out over the festive period which closed the Thameslink route across central London from the last train on Christmas Eve until the first on New Year’s Eve.

The old junction to Moorgate at Farringdon was removed so the platforms can later be lengthened, ready for the first longer 12-car trains entering service in December 2011.

The sewer carrying the river Fleet underneath Farringdon station was diverted, making way for the new ticket hall due to open in 2012. This will serve not just Thameslink, but also Crossrail from 2017.

And a new ‘bi-directional’ signalling system was installed between St Pancras International and Kentish Town, allowing trains to travel in either direction over a section of track. This will make it easier to operate services at times of disruption and when the Thameslink route is closed across the centre of London.