A Tunneling Marathon under London

Meet Crossrail’s giant tunneling machines. Crossrail is a 73-mile (118km) railway line under development in London and the home counties of Berkshire, Buckinghamshire and Essex, England.

Crossrail will use eight tunnel boring machines (TBMs) to construct the new tunnels under London. These huge machines will work 24 hours a day beneath the streets, excavating large volumes of ground and erecting the concrete tunnel lining.

Each machine has a rotating cutter head at the front, and a series of trailers behind, housing all the mechanical and electrical equipment required for the excavation of material.

To construct the 26 mile (42km) of tunnel required for Crossrail, the TBMs will undertake ten individual tunnel drives to construct the 20.3 foot (6.2m) diameter rail tunnels.

Each TBM weighs approximately 1,102 tons (1,000 tonnes) and will be up to 459 feet (140m) in length with an external diameter of 23.3 feet (7.1m). This allows for an inside tunnel diameter of 20.3 foot (6.2m) once the concrete tunnel segments are in place.

The TBM will be operated by a ‘tunnel gang’ comprising of around twenty people – twelve people on the TBM itself and eight people working from the rear of the machine to above ground. Have a look below on how the project is going to be constructed:

Upon project completion, a large portion of the line, between Paddington in central London and Abbey Wood in the south-east, is due to open in Autumn 2019. At the time of this opening, that new section and two other existing routes will be officially renamed the Elizabeth line, after Queen Elizabeth II.

The Elizabeth line – which will be London’s newest railway, will stop at 41 accessible stations, 10 newly built and 30 newly upgraded, and is expected to serve around 200 million people each year. The line will make traveling in the capital easier and quicker and will reduce crowding on London’s transport network.

So, the next time you’re in London, be sure to ride the Crossrail and experience the tunneling engineering excellence.

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