Euston Tunnel

{{Use British English|date=August 2021}} {{Use dmy dates|date=August 2021}} {{Infobox tunnel | name = Euston Tunnel | image = HS2 Euston tunnel.png | image_size = | alt = | caption = HS2 route out of Euston via Old Oak Common | official_name = | other_name = | line = | location = | coordinates = {{coord|51.537|-0.192|display=inline,title}} | os_grid_ref = | status = Under construction | system = [[High Speed 2]] | crosses = West London | start = [[Euston railway station]] | end = [[Old Oak Common railway station]] | stations = | startwork =27 January 2026 (boring) | opened =  | closed =  | rebuilt = | reopened =  | owner = | operator = | traffic = High-speed passenger trains | character = | engineer = | construction = | length = {{convert|7.2|km|mi}} | linelength = | tracklength = | notrack = 2 [[single track (rail)|single-track]] tunnels | gauge = {{Track gauge|Standard gauge}} | el = {{25 kV 50 Hz AC}} | speed ={{convert|120|kph|round=5|abbr=on}} | hielevation = | lowelevation = | height = | width = {{convert|7.55|m|ft}} (internal) | depth_below_water = | shipping_clearance_above = | grade =−3.40% to +3.50%<ref>{{Cite web |date=2016-08-09 |title=HS2 Phase One: updated plan and profile maps for London Metropolitan 2016 |url=https://www.gov.uk/government/publications/hs2-plan-and-profile-maps-post-house-of-commons-select-committee-2016-london-metropolitan |access-date=2026-01-22 |website=GOV.UK |language=en}}</ref> | map = |cross_passages=18}} '''Euston Tunnel''' is a [[tunnel]] currently under construction in [[London]] that will carry the [[High Speed 2]] (HS2) railway between [[Euston railway station]] and [[Old Oak Common railway station]].

Work to prepare the site for construction was undertaken in the late 2010s, such as the clearance of the old carriage sheds near Euston station in 2018. A legal challenge to the tunnel's design was defeated in mid-2020. During October 2020, HS2 Ltd ordered the two [[tunnel boring machine]]s (TBMs) from [[Herrenknecht]] that will excavate the tunnel. Excavation of the tunnels began on 27 January 2026.

==History== To bring the HS2 high speed line into London, it was decided that a series of twin-bore tunnels underneath the city would be the most practical approach.<ref name="global railway review"/> These will have a combined total of {{convert|42|km|mi}}, roughly equivalent in length to those built for the [[Crossrail]] programme. Responsibility for the construction of the section between central London and the [[M25 motorway|M25]] has been assigned to HS2's main works contractor, Skanska Costain STRABAG JV. In total, it has been envisaged that ten [[tunnel boring machine]]s (TBMs) will be used to bore the {{convert|102|km|mi}} of tunnelling along the HS2 route between the West Midlands and London.<ref name="global railway review"/><ref>{{cite web |url = https://www.hs2.org.uk/building-hs2/tunnels/london-tunnels/ |title = London tunnels |publisher = hs2.org.uk |accessdate = 10 October 2021}}</ref>

=== Preparatory works === During 2018, the disused [[Euston Downside Carriage Maintenance Depot]], close to Euston railway station, was demolished in order to clear space for the future construction work; the tunnel portal of the future Euston Tunnel is to be present at this location.<ref>{{cite web |url = https://www.roofingtoday.co.uk/first-look-at-hs2s-euston-tunnel-site-video/ |title = First Look at HS2’s Euston Tunnel Site (Video) |publisher = roofingtoday.co.uk |date = 5 October 2018}}</ref>

During 2019, a legal challenge to the design of Euston Tunnel was launched by a local resident, alleging failures to address safety concerns;<ref>{{cite web |url = https://www.architectsjournal.co.uk/news/homeowner-clears-legal-hurdle-in-bid-to-stop-catastrophic-euston-tunnel-design |title = Homeowner clears legal hurdle in bid to stop ‘catastrophic’ Euston tunnel design |publisher = architectsjournal.co.uk |date = 20 January 2020 |first = Rob |last = Horgan}}</ref> in June 2020, the [[High Court]] dismissed the challenge as "impossible to accept".<ref>{{cite web |url = https://environment-analyst.com/uk/105697/high-court-backs-hs2-in-euston-tunnel-case |title = High Court backs HS2 in Euston tunnel case |publisher = environment-analyst.com |date = 10 June 2020}}</ref>

During October 2020, HS2 Ltd signed a contract with the manufacturing group [[Herrenknecht]] to build and supply the two TBMs for Euston Tunnel.<ref name="global railway review"/> These are to be custom-designed to suit the local [[geology]], which ground surveys indicated to consist largely of [[London Clay]] and [[chalk]], with which the tunnels are to be bored through.<ref name="global railway review"/> Delivery of the two TBMs was originally scheduled to take place sometime in late 2021.<ref name="global railway review"/>

Between August 2021 and December 2033, a portion of [[London Zoo]]'s car park is to be temporarily borrowed for use by construction vehicles while Euston Tunnel is being built.<ref name="hs2 euston">{{cite web |url = https://www.hs2.org.uk/in-your-area/local-community-webpages/hs2-in-camden/euston-approaches/ |title = Euston approaches |publisher = hs2.org.uk |accessdate = 10 October 2021}}</ref>

=== Hiatus === Work was paused in 2023, and was later announced that the line would not be extended into Euston without private funding.<ref>{{Cite news |last=Knott |first=Jonathan |date=2023-04-17 |title=HS2 admits Euston Tunnel construction is paused |url=https://www.constructionnews.co.uk/civils/hs2-admits-euston-tunnel-construction-is-paused-17-04-2023/ |work=[[Construction News]]}}</ref><ref>{{Cite news |last=Race |first=Michael |last2=Austin |first2=Katy |date=2023-10-05 |title=HS2 will not go to Euston without private funds |url=https://www.bbc.co.uk/news/business-67021225 |work=[[BBC News]]}}</ref> The two TBMs needed for the tunnels were lowered into the Old Oak Common station site in summer 2024, awaiting approval for the tunnels, to allow work on the rest of the station to progress.<ref>{{Cite news |last=Daly |first=Patrick |date=2023-08-10 |title=Diggers to be buried at HS2 station to await green light on Euston extension |url=https://www.independent.co.uk/news/uk/old-oak-common-euston-huw-edwards-hs2-london-b2390978.html |work=[[The Independent]]}}</ref><ref name=":0">{{Cite news |last=Simmons |first=Mark |date=2024-10-30 |title=British government commits to HS2 central London tunnels |url=https://www.railjournal.com/financial/british-government-commits-to-hs2-central-london-tunnels/ |work=[[International Railway Journal]] |url-access=subscription}}</ref>

In the [[October 2024 United Kingdom budget|Autumn 2024 budget]], funding commitments to complete the tunnelling were made, with a view for preparatory work to be completed by the end of the year and for tunnelling to begin from 2025.<ref name=":0" /> In February 2025, work on the tunnels was again paused with funding diverted to the section from Old Oak Common to Birmingham Curzon Street.<ref>{{Cite web |last=Prior |first=Grant |date=2025-02-25 |title=HS2 Euston tunnel work put on hold |url=https://www.constructionenquirer.com/2025/02/25/hs2-euston-tunnel-work-put-on-hold/ |access-date=2025-11-01 |website=Construction Enquirer |language=en-GB}}</ref>

== Design == The tunnel will be {{convert|7.2|km|mi}} long, with an internal diameter of {{convert|7.55|m|ft|abbr=on}}. At its deepest point, the tunnel will run {{convert|66|m|ft|abbr=on}} below ground.<ref name=":4">{{Cite web |date=2026-03-16 |title=HS2 launches final giant tunnelling machine towards Euston station |url=https://mediacentre.hs2.org.uk/news/hs2-launches-final-giant-tunnelling-machine-towards-euston-station |access-date=2026-03-16 |website=HS2}}</ref> The tunnel will have 18 cross-passages.<ref name=":2">{{Cite web |date=9 December 2025 |title=Euston Tunnel: Frequently asked questions |url=https://www.hs2.org.uk/about-us/documents/euston-tunnel-frequently-asked-questions/ |access-date=2026-01-27 |website=HS2 |language=en-GB}}</ref>

The tunnel will have two intermediate ventilation shafts with associated headhouses, namely [[Adelaide Road]] Vent Shaft, in [[Swiss Cottage]], and Canterbury Road Vent Shaft, in [[Kilburn, London|Kilburn]].<ref name=":2" />

The Euston Portal headhouse will also serve to provide ventilation and emergency access, featuring [[Staffordshire blue brick|Staffordshire blue brickwork]], dark metal panels, a noise screen, and a green roof. About 400 m to the north, a second Euston Cavern headhouse will provide additional emergency access. A third headhouse that had been planned for this area has since been removed from the scheme. Unlike other HS2 tunnels, the up and down lines are at different levels, and the headhouses provide multiple points of access.<ref>{{Cite web |date=8 July 2024 |title=Euston Portal headhouse: Frequently asked questions |url=https://www.hs2.org.uk/about-us/documents/euston-portal-headhouse-frequently-asked-questions/ |access-date=2026-01-27 |website=HS2 |language=en-GB}}</ref><ref>{{Cite web |date=20 October 2022 |title=Euston Cavern Headhouse Final design – You Said, We Did {{!}} August 2022 |url=https://assets.hs2.org.uk/wp-content/uploads/2022/10/Euston-Cavern-Headhouse-updated-final-design-Aug-2022.pdf |website=HS2}}</ref>

==Construction== Euston Tunnel will be bored using [[tunnel boring machine]]s launched from the western entrance, near [[Old Oak Common railway station]].<ref name="global railway review">{{cite web |title=Giant tunnelling machines contract for London tunnels signed by HS2 Ltd |url=https://www.globalrailwayreview.com/news/110833/tunnelling-machines-contract-london-hs2/ |publisher=Global Railway Review |access-date=16 August 2021 |date=12 October 2020}}</ref>

The pre-cast concrete sections lining the tunnel were manufactured by [[Strabag]] at their factory in [[Hartlepool]].<ref>{{Cite web |date=2023-07-24 |title=Production of HS2 tunnel segments begins at new STRABAG facility in Hartlepool |url=https://mediacentre.hs2.org.uk/news/production-of-hs2-tunnel-segments-begins-at-new-strabag-facility-in-hartlepool |access-date=2026-01-27 |website=HS2 |language=}}</ref> 48,294 concrete ring segments will be used to form 8,049 rings to line the tunnels and over 1.5 million tonnes of material will be removed during construction.<ref name=":3">{{Cite web |date=2026-01-27 |title=Next stop Euston. HS2 begins tunnelling to central London |url=https://mediacentre.hs2.org.uk/news/next-stop-euston-hs2-begins-tunnelling-to-central-london |access-date=2026-01-27 |website=HS2 |language=}}</ref> The use of [[3D printing]] technology was trialled to reduce the amount of concrete used in Euston Tunnel in comparison to traditional methods.<ref>{{cite web |url = https://www.ianvisits.co.uk/articles/hs2-to-use-3d-printing-at-euston-station-tunnels-46218/ |title = HS2 to use 3D printing at Euston station tunnels |publisher = ianvisits.co.uk |date = 10 August 2021}}</ref>

In advance of the tunnel's boring, a smaller {{convert|853|m|ft|abbr=on}} long logistics tunnel was bored using a separate smaller TBM that will facilitate access between the primary construction compound at Atlas Road and Old Oak Common Station, the launch site for the Northolt East and Euston TBMs, through which construction materials such as the precast concrete lining segments will be brought into the site and [[wiktionary:spoil|spoil]] removed.<ref>{{Cite web |title=Atlas Road Logistics Tunnel |url=https://www.hs2.org.uk/building-hs2/tunnels/atlas-road-logistics-tunnel/ |access-date=2023-09-17 |website=HS2 |language=en-GB}}</ref><ref name="reconnect 2021">{{cite web |last=Long Branch |first=Mike |date=22 February 2021 |title=HS2 Prepares for 21km tunnels under London (Tunneltalk) |url=https://www.londonreconnections.com/2021/hs2-prepares-for-21km-tunnels-under-london-tunneltalk/ |publisher=londonreconnections.com}}</ref> Boring on the Atlas Road Logistics tunnel began with the launch of TBM ''Lydia'' (formerly TBM ''Ellie'' on the [[Crossrail]] project before being refurbished for HS2 by Herrenknecht) on 12 April 2023, and finished on 23 January 2024.<ref>{{Cite web |title=Crossrail TBM upcycled for HS2 logistics tunnel drive |url=https://www.constructionenquirer.com/2023/04/13/crossrail-tbm-upcycled-to-aid-hs2-main-drive/ |access-date=2023-09-17 |website=Construction Enquirer |language=en-GB}}</ref><ref>{{Cite web |last=May |first=Tiana |date=2023-04-13 |title=HS2 Launches Third Tunnel Boring Machine in London |url=https://railway-news.com/hs2-launches-third-tunnel-boring-machine-in-london/ |access-date=2023-09-17 |website=Railway-News |language=en-gb}}</ref><ref>{{Cite news |date=2024-01-23 |title=HS2: Tunnel completion takes line closer to Euston, engineers say |url=https://www.bbc.com/news/uk-england-london-68068833 |access-date=2024-01-23 |work=BBC News |language=en-GB}}</ref> Excavated material will be removed via a conveyor belt installed within the Atlas Road Logistics tunnel, and transported to [[Willesden Logistics Hub|Willesden Euro Terminal]] for re-use in Kent, Cambridgeshire and Rugby.<ref name=":1">{{Cite web |title=Euston Tunnel |url=https://www.hs2.org.uk/building-hs2/tunnels/tunnel-drives/euston-tunnel/ |access-date=2024-12-03 |website=HS2 |language=en-GB}}</ref>

Two {{convert|198|m|ft|abbr=on}} long TBMs supplied by [[Herrenknecht]] will be used to bore the tunnels, with a cutterhead diameter of {{convert|8.53|m|ft|abbr=on}} and weighing {{convert|1624|t|LT}} each. They are named ''Karen'' after [[Karen Harrison]], the UK's first female train driver, and ''Madeline'' after [[Madeleine Nobbs|Madeline Nobbs]], former president of the [[Women's Engineering Society|Women’s Engineering Society]].<ref name=":1" /><ref name=":3" /><ref name=":4" />

The TBMs are expected to take 18 months to excavate the tunnels and are planned to reach the Euston cavern by June 2027. ''Madeline'' began excavation of the upline tunnel from Old Oak Common station on 27 January 2026, and will advance at an average speed of {{convert|16|m|ft|abbr=on}} per day. The launch was attended by the Chief Secretary to the Prime Minister, [[Darren Jones]], and the Rail Minister, [[Peter Hendy|Lord Hendy]].<ref>{{Cite web |last=Johnson |first=Thomas |date=2026-01-27 |title=First TBM for HS2 tunnelling to central London launched |url=https://www.newcivilengineer.com/latest/first-tbm-for-hs2-tunnelling-to-central-london-launched-27-01-2026/ |access-date=2026-01-27 |website=New Civil Engineer |language=en}}</ref><ref>{{Cite web |last=Austin |first=Katy |date=2026-01-27 |title=HS2: Construction begins on tunnel from west London to Euston |url=https://www.bbc.co.uk/news/articles/cp87pyp40zko |access-date=2026-01-27 |website=BBC News |language=en-GB}}</ref> ''Karen'' began excavation of the downline tunnel on 16 March 2026, in a ceremony attended by two female train drivers from [[Avanti West Coast]].<ref name=":4" />

==References== <references /> {{High Speed 2 articles}}

[[Category:Railway tunnels in London]] [[Category:Tunnels on High Speed 2]]