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Western Rail Link to Heathrow

Network Rail

The Western Rail Link to Heathrow is a new two-track rail line from Langley Station on the Great Western Main Line to an end-on connection with the existing Heathrow Express line at the west end of Heathrow Terminal 5 Station. The structures along the route include retained cut (400m), C&C tunnel (500m), twin bored TBM tunnel (4km) and two temporary shafts that will be used to recover the TBMs. The final 160m-long section of the tunnel will be an open face excavation with SCL which connects into existing stub tunnels at Heathrow Terminal 5 Station. Within the alignment of the bored tunnels two intervention/ventilation shafts, eight cross passages and four ventilation adits will also be constructed. The TBM tunnels pass beneath the M4 and M25 Motorways. The proposed line-speed is 75 mph.

Consultancy Services for Tunnels and Underground Structures to Network Rail:

The scope of consultancy services of Gall Zeidler Consultants to Network Rail comprises of review of the Approval-in-Principle design, producing contract requirements for tunnels and underground structures, pre-qualification/tender assessment and development of Geotechnical Baseline Report to assist their project procurement process.


London, UK


2019 - Present


New railway line - TBM / SCL / Cut & Cover tunnels, shafts, cross passages, adits and retained cut.


6.5 km


Tunnels - TBM (6.5m ID), SCL (6.8m ID), C&C (10-28m wide by 7.2-8.7m high)


Superficial deposits of 5-10m thick, underlain by Tertiary sediments (London Clay and Lambeth Group) of 40-50m thick. TBM / SCL tunnels are wholly constructed in heavily overconsolidated London Clay.


Est. £ 900m


Network Rail


Network Rail