{{Short description|Twin-bore tunnel for HS2 railway}} {{Use British English|date=December 2024}} {{Use dmy dates|date=December 2024}} {{Infobox tunnel|line=[[High Speed 2]]|location=[[United Kingdom]] ([[Warwickshire]], [[West Midlands (county)|West Midlands]])|start=[[Water Orton]], [[North Warwickshire]]|end=[[Washwood Heath]], [[Birmingham]]|length={{convert|5.8|km|mi|abbr=in}}|traffic=High-speed passenger trains|speed={{convert|230|kph|round=5|abbr=on}}|status=Under construction|coordinates={{coord|52.5133|-1.7524}} (east portal) {{ubl|{{coord|52.5038|-1.8344|display=inline,title}} (west portal)}}|startwork=July 2023 (boring)|construction=22 November 2021 – present|width={{convert|7.75|m|ft}} (internal)|gauge={{Track gauge|sg|al=on|allk=on}}|el={{25 kV 50 Hz AC}}|crosses=[[M6 motorway]]<br/>[[River Tame, West Midlands|River Tame]]<br/>[[Park Hall Nature Reserve]]|notrack=2 [[single track (rail)|single-track]] tunnels|cross_passages=13}}
'''Bromford Tunnel''' is a high-speed railway tunnel in [[North Warwickshire]] and [[Birmingham]], England that will serve to bring the [[High Speed 2]] rail line into Birmingham upon completion.
The {{convert|5.8|km|mi|abbr=in}} twin-bore tunnels are situated between [[Water Orton]] and [[Washwood Heath]]. The tunnels were excavated between July 2023 and October 2025.
== History == The contract to build the tunnel, as part of the wider N1 and N2 lots on the HS2 programme, was awarded to the [[Balfour Beatty]] [[Vinci SA|Vinci]] JV on 1 April 2020, valued at {{circa|£5{{nbsp}}billion}}.<ref>{{Cite web |date=2020-04-15 |title=Balfour Beatty - VINCI joint venture is awarded the contract for HS2's main civil engineering works packages lots N1 and N2 in the United Kingdom |url=https://www.vinci.com/en/newsroom/press-releases/balfour-beatty-vinci-joint-venture-awarded-contract-hs2s-main-civil |access-date= |website=[[Vinci SA]] |language=}}</ref> This followed them being named by HS2 as part of the intention to award in July 2017.<ref>{{Cite web |date=2017-07-17 |title=Balfour Beatty joint venture to be awarded HS2 contracts valued at c. £2.5 billion |url=https://www.balfourbeatty.com/media-centre/latest/balfour-beatty-joint-venture-to-be-awarded-hs2-contracts-valued-at-c-25-billion/ |access-date=2024-12-16 |website=[[Balfour Beatty]] |language=en-GB}}</ref>
The route was initially envisioned in the [[High Speed Rail (London - West Midlands) Act 2017]] to be a tunnel, {{convert|2.86|km|mi|abbr=in}} long (in Work No. 3/203) and partly on viaduct, less than {{convert|30|m|ft|abbr=on}}, in length (in Work No. 3/157).<ref>{{Cite web |title=High Speed Rail (London - West Midlands) Act 2017 |url=https://www.legislation.gov.uk/ukpga/2017/7/schedule/1/enacted |archive-url=https://web.archive.org/web/20181126065327/http://www.legislation.gov.uk/ukpga/2017/7/schedule/1/enacted |archive-date=26 November 2018 |access-date= |website=www.legislation.gov.uk |language=en}}</ref><ref name=":0">{{Cite web |date=20 January 2022 |title=Bromford Tunnel Transport and Works Act Order Application |url=https://www.hs2.org.uk/documents/collections/bromford-tunnel-transport-and-works-act-order-application/ |access-date= |website=HS2 |language=en-GB}}</ref>
On 20 January 2022, HS2 Ltd made a [[Transport and Works Act 1992|Transport and Works Act]] Order application to remove the words "partly on viaduct" in the description of the works, in a bid to extend the tunnel by {{convert|3.1|km|mi|abbr=in}} instead.<ref name=":0" /> This decision was claimed to reduce land take, minimise impacts on the [[Park Hall Nature Reserve]], avoid the need to redirect the [[River Tame, West Midlands|River Tame]], and reduce construction traffic.<ref name=":1">{{Cite web |title=Bromford Tunnel |url=https://www.hs2.org.uk/building-hs2/tunnels/tunnel-drives/bromford-tunnel/ |access-date= |website=[[HS2]] |language=en-GB}}</ref>
The plans were refused by North Warwickshire Borough Council and subsequently dismissed on appeal by Grahame Gould, an inspector of the [[Planning Inspectorate]] in March 2023. The [[Secretary of State for Housing, Communities and Local Government|Secretary of State for Levelling Up, Housing and Communities]] and [[Secretary of State for Transport]] recovered the appeal to these plans and Schedule 17 approval was granted on 14 May 2024.<ref>{{Cite web |last1=Barber |first1=Phil |last2=Stewart |first2=Paul |date=14 May 2024 |title=Appeal made by High Speed Two Limited (HS2 Ltd) against the decision of North Warwickshire Borough Council to decline to determine the request for the approval of plans and specifications made under Schedule 17, comprising the Water Orton cutting, including the Bromford Tunnel east portal and Attleboro Lane overbridge and ancillary works. |url=https://assets.publishing.service.gov.uk/media/66434e3ef34f9b5a56adc6b6/Recovered_appeal_-_Bromford_Tunnel_extension_at_Water_Orton_Cutting.pdf |website=GOV.UK}}</ref><ref name=":6">{{Cite web |last=Hakimian |first=Rob |date=2025-09-05 |title=HS2 {{!}} Council squandered over £100k of public money fighting Bromford tunnel extension |url=https://www.newcivilengineer.com/latest/hs2-council-squandered-over-100k-of-public-money-fighting-bromford-tunnel-extension-05-09-2025/ |access-date=2025-09-06 |website=New Civil Engineer |language=en}}</ref> The council applied for a judicial review, which was heard over three days in the [[High Court of Justice|High Court]] in February 2025 by [[Ian Dove|Justice Dove]]. The council claimed that HS2 did not have the correct authorisation to extend the tunnel; however, the case was dismissed on all grounds on 20 May 2025.<ref>{{Cite web |date=20 May 2025 |title=North Warwickshire Borough Council v Secretary of State for Transport & Anor EWHC (20 May 2025) |url=https://www.bailii.org/ew/cases/EWHC/Admin/2025/1248.pdf |website=BAILII}}</ref> As of 2025, North Warwickshire Borough Council has spent £116,740 of taxpayer money on the case and has sought permission from the [[Court of Appeal (England and Wales)|Court of Appeal]] to appeal the ruling.<ref name=":6" />
The two [[Herrenknecht]] tunnel boring machines (TBMs) used to construct the tunnel were named ''Mary Ann'', after Mary Ann Evans (with the pen name, [[George Eliot]]) and ''Elizabeth'', after [[Elizabeth Cadbury]].<ref>{{Cite news |date=14 June 2023 |title=HS2 unveils huge tunnel boring machine ready to dig HS2's Bromford Tunnel in the West Midlands |url=https://mediacentre.hs2.org.uk/news/hs2-unveils-huge-tunnel-boring-machine-ready-to-dig-hs2s-bromford-tunnel-in-the-west-midlands |work=[[HS2]]}}</ref><ref>{{Cite news |date=5 March 2024 |title=The last HS2 tunnel boring machine in the West Midlands starts digging towards Birmingham |url=https://mediacentre.hs2.org.uk/news/the-last-hs2-tunnel-boring-machine-in-the-west-midlands-starts-digging-towards-birmingham |work=[[HS2]]}}</ref> Most of the second TBM to be delivered, ''Elizabeth'', was repurposed from TBM ''Dorothy'' used to construct the [[High Speed 2#Long Itchington Wood tunnel|Long Itchington Wood tunnel]], with a new outer cutter-head and shield ordered.<ref>{{Cite magazine |last=Smart |first=Belinda |date=26 November 2024 |title=How UK and international tunnelling projects are reducing their environmental impacts |url=https://www.newcivilengineer.com/in-depth/how-uk-and-international-tunnelling-projects-are-reducing-their-environmental-impacts-26-11-2024/ |magazine=[[New Civil Engineer]]}}</ref><ref name=":2">{{Cite web |date=12 December 2023 |title=Balfour Beatty VINCI gets second giant HS2 tunnel boring machine ready to start digging |url=https://www.balfourbeatty.com/media-centre/latest/balfour-beatty-vinci-gets-second-giant-hs2-tunnel-boring-machine-ready-to-start-digging-under-birmingham/ |access-date= |website=Balfour Beatty |language=en-GB}}</ref>
== Design == The tunnel passes underneath the Park Hall Nature Reserve, River Tame, and [[M6 motorway]], and runs up to {{convert|40|m|ft|abbr=on|sigfig=3}} underground.<ref name=":3">{{Cite news |last=Plisner |first=Peter |date=30 August 2024 |title=HS2 Bromford Tunnel reaches halfway mark |url=https://www.railmagazine.com/news/2024/08/30/hs2-bromford-tunnel-reaches-halfway-mark |work=[[Rail (magazine)|Rail]]}}</ref>
The tunnel will have 13 cross-passages, spaced every {{convert|500|m|ft|abbr=on|sigfig=3}}, and {{convert|5.5|m|ft|abbr=on|sigfig=3}} wide, as well as 8 [[Adit|adits]].<ref name=":4">{{Cite web |title=High Speed 2 Contracts N1 & N2 |url=https://www.gzconsultants.com/wp-content/uploads/1942-HS2NC-1.pdf |archive-url=https://web.archive.org/web/20241216230421/https://www.gzconsultants.com/wp-content/uploads/1942-HS2NC-1.pdf |archive-date=16 December 2024 |website=Gall Zeidler Consultants}}</ref>
The western portal at Washwood Heath sits next to the [[Washwood Heath depot]] and Network Integrated Control Centre, where trains will be maintained and stored and where operational control of the line will be based.<ref name=":5" />
The eastern portal at Water Orton will have a porous portal, likely in the form of a perforated concrete structure, to mitigate [[tunnel boom]] associated with trains travelling at {{convert|230|kph|abbr=on|round=5}}.<ref name=":1" /><ref name=":3" />
The decision to extend the tunnel to over 3 km resulted in the need for an intermediate shaft to allow for adequate airflow.<ref>{{Cite web |last=Cartwright |first=Mark |date=9 December 2024 |title=Bromford Tunnel extension - design and environmental benefits with no additional land take |url=https://learninglegacy.hs2.org.uk/document/bromford-tunnel-extension-design-and-environmental-benefits-with-no-additional-land-take/ |access-date= |website=HS2 Learning Legacy |language=en-GB}}</ref> The tunnel will have a {{convert|47|m|ft|abbr=on}} deep, {{convert|18.6|m|ft|abbr=on}} diameter ventilation shaft at [[Castle Vale]], around the halfway point of the tunnel. The headhouse, located in the Castle Bromwich Business Park, will have pre-cast concrete walls with an overlaid "flexi-brick" lattice facade made of ceramic tiles and a 'green roof'.<ref>{{Cite news |last=Thomas |first=Tris |date=28 August 2024 |title=HS2's Bromford Tunnel TBM reaches halfway |url=https://tunnellingjournal.com/hs2s-bromford-tunnel-tbm-reaches-halfway/ |work=Tunnelling Journal}}</ref><ref>{{Cite web |date=4 March 2023 |title=Building works associated with the construction of an intermediate shaft headhouse building serving the Bromford Tunnel along with associated lighting, security fencing, bollards and road vehicle parking |url=http://eplanning.idox.birmingham.gov.uk/publisher/mvc/listDocuments?identifier=Planning&reference=2023/08527/PA |website=[[Birmingham City Council]]}}</ref>
== Construction == Tunnelling and excavation was primarily through [[Mercia Mudstone Group|Mercia Mudstone]], at mostly [[British Geological Survey|BGS]] grade II weathering. The [[Water table|groundwater]] level is, at most, {{convert|30|m|ft}} above the tunnels' roof.<ref name=":4" />
The variable pressure TBMs used to construct the tunnel have a cutter-head diameter of {{cvt|8.62|m|ft}}, with a length of {{cvt|125|m|ft}} and weigh approximately 1,600{{nbsp}}tonnes each. They were both expected to take 16{{nbsp}}months to complete the tunnel, employing around 450{{nbsp}}people.<ref name=":2" /><ref>{{Cite web |date=14 June 2023 |title=HS2 unveils huge tunnel boring machine ready to dig HS2’s Bromford Tunnel in the West Midlands |url=https://mediacentre.hs2.org.uk/news/hs2-unveils-huge-tunnel-boring-machine-ready-to-dig-hs2s-bromford-tunnel-in-the-west-midlands |access-date=2025-05-22 |website=HS2 News and Information |language=english}}</ref>
The TBM ''Mary Ann'' started boring in July 2023 from an underground box structure, measuring {{convert|160|x|30|x|15|m|ft|abbr=on}}, at the eastern portal in Water Orton, towards the {{convert|22|m|ft|abbr=on}} deep portal at Washwood Heath. This was followed by TBM ''Elizabeth'' in March 2024.<ref name=":5">{{cite web |title=HS2 celebrates first Birmingham tunnel breakthrough |url=https://mediacentre.hs2.org.uk/news/hs2-celebrates-first-birmingham-tunnel-breakthrough |access-date=9 May 2025 |website=HS2 News and Information |language=english}}</ref><ref>{{Cite web |title=Balfour Beatty VINCI unveils huge tunnel boring machine ready to dig HS2's Bromford Tunnel in the West Midlands |url=https://balfourbeattyvinci.co.uk/balfour-beatty-vinci-unveils-huge-tunnel-boring-machine-ready-to-dig-hs2s-bromford-tunnel-in-the-west-midlands/ |access-date= |website=Balfour Beatty VINCI}}</ref><ref>{{Cite news |date=6 March 2024 |title=HS2's "Elizabeth" Begins Digging Second Birmingham Tunnel |url=https://www.railtechnologymagazine.com/articles/hs2s-elizabeth-begins-digging-second-birmingham-tunnel |work=Rail Technology Magazine}}</ref>
A total of 40,628 concrete segments, weighing up to 7{{nbsp}}tonnes each, produced by the joint venture's pre-cast concrete factory in [[Avonmouth]], [[Bristol]], were used to support the tunnels. These formed 5,804 rings, weighing 49{{nbsp}}tonnes each. Forty percent of the cement used was replaced with [[ground granulated blast-furnace slag]] (GGBS), claimed to reduce the overall carbon footprint involved.<ref name=":2" /><ref name=":7">{{Cite web |date=2025-10-13 |title=HS2 celebrates final Birmingham tunnel breakthrough |url=https://mediacentre.hs2.org.uk/news/hs2-celebrates-final-birmingham-tunnel-breakthrough |access-date=2025-10-13 |website=HS2 |language=}}</ref> The TBMs excavated 1.8{{nbsp}}million{{nbsp}}tonnes of material, which was treated by the on-site slurry treatment plant for use on HS2's delta junction, south of Water Orton, and conveyed on dedicated haul roads.<ref name=":5" /><ref>{{Cite web |date=9 September 2024 |title=HS2 completes first viaduct structures at Delta Junction |url=https://mediacentre.hs2.org.uk/news/hs2-completes-first-viaduct-structures-at-delta-junction |access-date= |website=HS2 News and Information |language=}}</ref><ref name=":7" />
''Mary Ann'' broke through on 9 May 2025, after advancing at a peak of {{cvt|30|m}} per day, while ''Elizabeth'' broke through on 13 October 2025.<ref name=":1" /><ref name=":5" /><ref name=":7" />
== See also ==
* [[Washwood Heath depot]] * [[Birmingham Curzon Street railway station]]
== References == {{reflist}} {{High Speed 2 articles}}
[[Category:Tunnels on High Speed 2]] [[Category:Tunnels in Warwickshire]] [[Category:Tunnels in Birmingham, West Midlands]] [[Category:Buildings and structures under construction in the United Kingdom]]