TBM tunnel enlargement

At the beginning of August Fillie, a 9 m-diameter TBM, started work near Bolton, UK as part of a Network Rail project to electrify the Preston-Bolton-Manchester line, one of north-west England’s busiest rail routes.
Upgrading the railway through Farnworth posed a particular engineering challenge, as the twin tunnels which carry the railway under the main A666 Manchester to Bolton road aren’t big enough to accommodate the overhead lines which will power a new fleet of electric trains in future.
The reconstruction of Farnworth tunnel is part of over EUR1.4bn of investment by Network Rail to improve rail services across the north, electrifying key routes, creating new rail links, improving stations and journeys. Network Rail will also be reconstructing a retaining wall, reconstructing a road bridge, making changes to both platforms at Farnworth Station, installing new track between Bolton and Moses Gate, making alterations at Moses Gate Station, and replacing a pedestrian level crossing near Kearsley with a footbridge.
Work on the Farnworth Tunnel commenced last 02.05.2015 and will end by 04.10.2015.
The 270 m-long smaller tunnel remains open during project work and will then be permanently closed.
The larger of the two tunnels was filled by 7,500 cu m of foam concrete, before boring operations commenced. The new tunnel, big enough for two tracks and their overhead power lines, is being re-bored through the new concrete by the TBM Fillie.

20/08/2015
Visit:http://www.networkrail.co.uk/news/2015/august/Britains-biggest-tunnel-boring-machine-starts-work-on-Bolton-railway-upgrade/ and http://www.networkrail.co.uk/.