Friday, July 8, 2011

UK - The 170th Anniversary of the Box Tunnel

When Isambard Kingdom Brunel designed the Great Western Railway he wanted to make it the straightest and flattest line as possible. A majority of the 118 mile line has gradients no steeper tan 1 in 1000. The buidling of the line was relatively straight forward until the final 24-mile section near Box in Wiltshire. The Box Tunnel was the largest and last major engineering work on the Great Western Railway and was a formidable obstacle in the railway's completion. One of the main factors for this apart from the rather steep 1 in 100 gradient was the fact that the lower levels of Box Hill comprise of an Oolithic limestone otherwise known as Bath Stone.

Work on the tunnel started in 1836, completely carried out by candlelight using only men and horses and took five years to complete. During that time 1500 men toiled day and night using a ton of gunpowder and candles a week! Tunneling began from both directions; George Burge of HErne Bay dug the western 2 kilometers with the eastern, more difficult section being dug by Brewer of Box and Lewis of Bath. When the ends of the two tunnels were joined by the accuracy of the design and work such that there was only a 5cm error in their alignment. the dramatic western portal near Box was designed in the classical style with the eastern portal being left as plain brick. At the time of its completion, it was the longest railway tunnel in existence at almost 2.9km long. It remains in use 170 years later. Box Tunnel is one of Brunel's masterpieces on the Great Western Railway, and despite its age still plays an important part in today's modern railway. My friend Stan sent me this commemorative cover.

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