Editing Box Tunnel (section)

{{Short description|Railway tunnel in western England}}
{{EngvarB|date=September 2013}}
{{Use dmy dates|date=October 2024}}
{{Infobox tunnel
|name         = Box Tunnel
|image        = BoxTunnelScape.jpg
|image_size   = 300px
|caption      = A winter view of the western portal
|line         = [[Great Western Main Line]]
|location     = [[Box Hill, Wiltshire]], England
|coordinates  = {{Coord|51.42128|N|2.22617|W|region:GB_type:landmark|display=inline,title}}
|system       =
|status       = Open, operational
|start        =
|end          =
|stations     =
|startwork    = December 1838
|opened = 30 June 1841
|close        =
|owner        = [[Network Rail]]
|operator     = Network Rail
|traffic      =
|character    =
|construction =
|length       = {{convert|1.83|mi|km}}
|linelength   =
|tracklength  =
|notrack      =
|gauge        =
|el           =
|speed        = {{convert|125|mph}}
|hielevation  =
|lowelevation =
|height       =
|grade        = 1:100
}}
[[Image:BoxTunnelWest.jpg|thumb|right|The west portal]]
'''Box Tunnel''' passes through [[Box Hill, Wiltshire|Box Hill]] on the [[Great Western Main Line]] (GWML) between [[Bath, Somerset|Bath]] and [[Chippenham]]. The {{Convert | 1.83 | mi | adj = on}} tunnel was the world's longest railway tunnel when it was completed in 1841.

Built between December 1838 and June 1841 for the [[Great Western Railway]] (GWR) under the direction of [[Isambard Kingdom Brunel]], the straight tunnel descends on a 1 in 100 gradient from its eastern end. At the time the tunnel's construction was considered dangerous due to its length and the composition of the underlying strata. The west portal is [[Grade II* listed]]<ref>{{NHLE|num=1271441|desc=West Portal of Box Tunnel|access-date=11 April 2017|mode=cs2|fewer-links=yes}}</ref> and the east portal is [[Grade II listed]].<ref>{{NHLE|num=1271441|desc=Box Tunnel East Portal (MLN19912)|access-date=11 April 2017|mode=cs2|fewer-links=yes}}</ref>

Ammunition was stored near the tunnel during [[World War II]], reusing mine workings. During the 2010s, the tunnel was modified and the track lowered to prepare it for electrification, although in 2016, this plan has been suspended for the time being.<ref name=dftelec>{{cite book |last=Department for Transport |title=Britain's transport infrastructure: Rail electrification |year=2009 |publisher=DfT Publications |location=London |isbn=978-1-84864-018-4 |page=30 |url=http://www.dft.gov.uk/pgr/rail/pi/rail-electrification.pdf |archive-url=http://webarchive.nationalarchives.gov.uk/20170123080842/http://www.dft.gov.uk/pgr/rail/pi/rail-electrification.pdf |url-status=dead |archive-date=23 January 2017}}</ref><ref name="BBC News">{{cite news |title=Box tunnel reopens after Network Rail electrification work |url=https://www.bbc.co.uk/news/uk-england-34112951 |publisher=BBC News |access-date=1 September 2015}}</ref>