Editing Summit Tunnel (section)

==Development==

[[File:Summit Tunnel ventilation shaft - geograph.org.uk - 739770.jpg|thumb|left|One of the tunnel's [[ventilation shaft]]s, 2008]]
Summit Tunnel, between Littleborough and Todmorden<ref name = "eng time"/> is the highest section of the {{convert|82|km|mi|order=flip|adj=on}} long [[Manchester and Leeds Railway]], which was built parallel to the [[Rochdale Canal]]. When built, it was the world's longest railway tunnel and a critical element of the first trans-Pennine line.<ref name = "eng time"/>

The tunnel was designed by the [[civil engineer]] [[Thomas Longridge Gooch]], a collaborator of [[George Stephenson]] and his son [[Robert Stephenson]] on several railway schemes.<ref name = "eng time"/> Between spring 1835 and 1844, Gooch was the engineer for the Manchester and Leeds Railway on behalf of George Stephenson, who was working on other projects. In September 1837, during Gooch's tenure, work commenced boring the tunnel.<ref name = "eng time"/> Gooch was assisted by Barnard Dickinson. When speaking about the tunnel, Dickinson exclaimed: "This tunnel will defy the rage of tempest, fire, war or wasting age".<ref name = "150 man">Thacker, Simon. [https://www.manchestereveningnews.co.uk/news/nostalgia/summit-tunnel-175-years-on-10959530 "The Summit tunnel 175 years on: The miracle of engineering which survived a devastating fire."] ''Manchester Evening News'', 28 February 2018. Retrieved 12 June 2018.</ref>

The tunnel is {{convert|1|mi|1,125|yd}} long and {{convert|6.6|m|ft|order=flip}} tall; the horseshoe-shaped bore is {{convert|7.9|m|ft|order=flip}} wide and accommodates a pair of tracks.<ref>{{cite book |last1=Kelman |first1=Leanne |editor1-last=Brailsford |editor1-first=Martyn |title=Midlands & North West |date=2018 |publisher=Trackmaps |location=Beckington, Frome |isbn=978-1-9996271-1-9 |edition=4|at=45A}}</ref>{{sfn|Edmondson|Sherratt|Roff|Levett|2018|p=51}}<ref>{{cite book |last1=Rennison |first1=Robert William |title=Civil engineering heritage. Northern England |date=1996 |publisher=Telford |location=London |isbn=0727725181 |page=195 |edition=2}}</ref> The tunnel falls on a gradient of 1-in-330 southwards (towards {{rws|Littleborough}}).{{sfn|Bairstow|2001|p=54}} It was driven by hand through shale, coal and sandstone, after which the walls were lined with six courses of brick, using more than 23 million bricks.<ref>''[https://books.google.com/books?id=mxIQAAAAYAAJ&pg=PA20 The Parliamentary Gazetteer of England and Wales]'', vol. 3, p. 20.  Edinburgh: A. Fullarton & Co., 1851.</ref> The bricks were handmade locally and up to 60,000 were laid in a single day.<ref name = "eng time"/> [[Roman cement]] was used for its [[Permeability (earth sciences)|impermeability]] to water. It has been estimated that about 8,100 tonnes (dry weight) of cement was transported to the tunnel from [[Kingston upon Hull|Hull]].<ref name = "eng time"/> During August 1838, James Wood, the chairman of the Manchester and Leeds Railway, laid the first brick in a ceremony.<ref name = "eng time"/>

[[File:40085 emerges from Summit Tunnel at Littleborough.jpg|thumb|A [[British Rail Class 40]] locomotive hauling a freight train through the tunnel, 8 June 1983]]
The original contractors were Evans, Stewart and Copeland.<ref name = "eng time"/> At the peak of construction, a workforce of between 800 and 1,250 men and boys was active, aided by about 100 horses and 13 stationary [[steam engine]]s, which were used to remove material from the shafts.<ref name = "eng time"/> The bedrock was hewn using physical strength and hand tools, illuminated only by candlelight. At an early stage of track laying, the rails were laid directly onto excavated rock, but conventional wooden [[Railroad tie|sleeper]]s were also used.<ref name = "eng time"/> The spoil was used for other purposes, including in the construction of [[Blackpool#Tourism|Blackpool Promenade]].<ref name = "eng time"/>

Alignment of the tunnel was achieved by drilling 14 vertical shafts to provide survey points.<ref name = "eng time"/> When the tunnel was complete, two shafts were sealed and the remaining 12 were retained as ventilation. The [[ventilation shaft]]s were up to {{convert|28|to|94|m|ft|order=flip}} deep. During the tunnel's service life, No.6 was sealed after rock falls.<ref name = "eng time"/>

Progress on construction was slower than expected; the [[bedrock]] and [[Shale|blue shale]] through which it was bored proved to be harder to excavate than anticipated.<ref name = "eng time"/> In March 1839, because of slow progress, the original contractors were dismissed and George Stephenson took over, after which the pace of work increased until a [[industrial action|strike]] of the [[bricklayer]]s occurred in March 1840.<ref name = "150 man"/> The last brick was laid on 9 December 1840.<ref name = "eng time"/>

Summit Tunnel should have opened on [[New Year's Eve]] 1840; but the opening was delayed after the discovery of a defective invert, {{convert|0.8|km|mi|1|order=flip}} from one end which had displaced the central track drain.{{sfn|Bairstow|2001|p=26}} After repairs, the tunnel was officially opened by Sir John Frederick Sigismund Smith, the government inspector of railways on 1 March 1841.{{sfn|Edmondson|Sherratt|Roff|Levett|2018|p=50}} Summit Tunnel cost £251,000 and the loss of 41 lives.<ref name = "eng time"/> The cost was far greater than the railway company expected.<ref name = "150 man"/>

The southern portal of the tunnel was grade II listed in 1986.<ref>{{NHLE|desc= Southern Entrance to Summit (Railway Tunnel) |num= 1162164|grade=II|access-date= 13 January 2022}}</ref>