Earlier this week a major milestone was reached at the Crossrail station in Canary Wharf: the station box was completed, some five months ahead of schedule. The site is now ready for the tunnel boring machines, which will arrive next year.
Built in the drained West India North Dock, Canary Wharf is, from an engineering perspective, one of the more challenging Crossrail stations. The bottom of the dock has been dug out to the depth of 28m, in order to lay the track bed where the trains will run; on top of the station there will be four levels of retail, culminating in the distinctive Norman Foster-designed timber lattice roof at surface level and a public park.
Construction work has been a challenge due to its location; as one engineer put it, having one of the world's most important trading floors as a neighbour somewhat reduces the amount of drilling that can be done, hence the need for non-disruptive engineering practices, such as the use of Giken piles to build the coffer dam in which the station box sits, isolating it from the rest of the dock.
The station's design, and the requirements for various flood-protection systems, has meant that, unusually, the station box needed to be constructed before the tunnel boring machines arrive. Our visit was a rare opportunity to see the completed job. Commuters will have to wait until 2018 before the first trains arrive.
Many thanks to Canary Wharf Group and Crossrail for arranging the visit.
Ian Visits was also on the tour; here's his report.