The line between Folkestone and Dover, built by William Cubitt, was a major engineering achievement, running close to the sea and at the foot of the cliffs. Its opening in 1844 completed the South Eastern Railway's main line to Dover. There were four tunnels on this section, Martello, Abbotscliffe, Shakespeare and Archcliffe. The first passes through gault clay and greensand and was more difficult to construct than the other three. It and Abbotscliffe are both double track tunnels. Due to less stable chalk, Shakespeare tunnels comprise two single track bores of unusual design. They are very tall, the crown being 28 feet above track level, and have Gothic cross-section.
Both Shakespeare and Abbotscliffe tunnels are close to the cliff face, so were constructed using horizontal access shafts, as well as the more normal vertical ones. Rubble was taken through the horizontal shafts to be transferred to boats for disposal. Construction of Abbotscliffe tunnel was disrupted by a strong spring, the Lydden Spout, breaking in. Archcliffe tunnels were two short, single bores, passing below Archcliffe Fort, Dover.
It was not just the tunnels that made the line an exceptional engineering feat. An unstable cliff face had to be removed between Abbot's Cliff and Shakespeare Cliff, which was achieved by detonating 8 tons of explosives packed into specially constructed chambers within the cliff. The open sections of line are protected by substantial sea walls and, more recently, by Samphire Hoe, the area of land between Abbot's Cliff and Shakespeare Cliff that was created by tipping spoil from the Channel Tunnel.
The line through Folkestone Warren was prone to landslips, usually minor. A landslide in January 1877 closed the line for three months, but by far the most serious slip occurred on 19th December 1915 when the line was moved seaward by up to 160 feet and partly buried under thousands of tons of chalk. Fortunately, neither Abbotscliffe nor Martello tunnels were damaged. Movement of the cliffs and the slipped material was noted until late 1917, but due to the war no action was taken to rebuild the line. Indeed, Shakespeare tunnels were taken over by the Admiralty for storing ammunition. The railway re-opened on 11th August 1919, following very extensive earthworks.
The railway was extensively modernised and rebuilt in Dover in 1927. This work included opening out Archcliffe tunnel.
Work has been undertaken since to prevent further slips, particularly during the period 1948 to 1954. Near Folkestone the chalk cliffs sit on gault, on which they can slide. Furthermore, the weight of the chalk can force the gault outwards. Headings into the cliffs drain away water that would otherwise lubricate the interface between chalk and gault. Other steps include reinforcing the railway formation to resist movement. Further work was undertaken during summer 2005, particularly to strengthen Abbotscliffe tunnel, where the cliff is moving outwards.
Some shafts, including number six, were rebuilt when the adjacent main road was constructed from Folkestone to Dover in 1993. The grille on top contains a locked hatch, to allow personnel access.
The narrow bores of Shakespeare Tunnel resulted in British Rail banning the operation of passenger trains without gangways through it, subject to an exception for a locomotive or motor luggage van at one end. This was because of the difficulty in evacuating trains through side doors in an emergency. The line was closed between Dover and Folkestone during summer 2009 while escape platforms were constructed inside the tunnel, thereby allowing the high-speed trains without end gangways to operate to Dover. Other repairs were undertaken to the tunnels at the same time.
All photographs are copyright
Also see the Railway Magazine September 1954 article on Coast Erosion Works in Folkestone Warren.
return to the Railway Structures menu
return to picture gallery page
This page was created 21 January 2010