Linslade Tunnel

The London and Birmingham Railway was opened in 1837. Robert Stephenson, the railway's chief engineer, was determined to keep the gradients on the route to a maximum of 1:330 which required significant engineering works. From the end of Tring Cutting to just south Leighton Buzzard railway station, the railway is carried on a series of embankments, after which it enters another deep cutting before reaching a small patch of sandstone high ground under Linslade Woods. A generation earlier, the Grand Junction Canal had followed the western edge of the floodplain of the River Ouzel, taking two fairly tight bends as a result. Once Stephenson was forced away from the town by local landowners, he was obliged to tunnel through the ridge to maintain his desired gradient and radius of curvature. The tunnel consists of three bores; the central bore was the first to be constructed and opened with the line in 1837. The contract for its construction was issued around 1834, one of the first contracts on the route. The central bore is long and was built wide enough to carry two tracks. It has a depth of roughly , its excavation involved the removal of 20,433 cubic yards (15,600 m3) of spoil. The tunnel portals at the northern end are heavily decorated. Above and around the openings is a red-brick retaining wall, except for the westernmost (the last one to be built) which is in blue brick. Above these is a blue-brick crennelated (castellated) parapet and a series of turrets flank the mouths of the portals. This use of blue brick suggests that the castellation was renewed when the westernmost tunnel was bored. The south portals are less elaborate but still decorated. They have significant batter (a sloping wall), rusticated voussoirs at the mouths and a rolled cornice above. ==History==

express emerging from Linslade Tunnel's southern portal, October 1948 During the 1960s, Linslade Tunnel, along with the majority of the West Coast Main Line, had overhead electrification apparatus installed, which facilitated the line's transition to electric traction. On 9 December 1982, during the British Rail era, there was a fatal incident at Linslade Tunnel: a load which had been loosened by hump shunting at Toton Sidings had fallen from one train and was struck by the next train passing through the tunnel, causing its derailment. The train hit a pier of the road bridge 100m to the north, killing its driver. During the late 2010s, deteriorated parts of the brickwork within Linslade Tunnel were repaired. In early 2020, there were more engineering works in the tunnel, largely focused on a comprehensive track renewal, to improve service reliability. Both portals are Grade II listed buildings. The north portal is cited as an "interesting example of early railway architecture". The south portal, although less intricate, is included for completeness. ==See also==