Editing Box Tunnel (section)

===Background===
During the 1830s, [[Isambard Kingdom Brunel]] developed a plan for a railway running east–west between London and Bristol.<ref name="eng time"/> The [[Great Western Main Line]] would maintain either level ground or gentle gradients of no greater than 1 in 1000 along most of its route. Between [[Swindon]] and [[Bath, Somerset|Bath]], at the highest point of the line, a tunnel was proposed through [[Box Hill, Wiltshire|Box Hill]], outside [[Corsham]].<ref name="eng time"/>

The tunnel would have a gradient of 1 in 100. At the time, the use of such a steep gradient inside the tunnel allegedly provoked criticism by some of Brunel's contemporaries.<ref name="eng time"/> Box Tunnel would be the longest railway tunnel at almost {{convert|1+3/4|mi}} in length.<ref name="eng time"/>