On 28 April 1953, the Clifton Hall Tunnel partially collapsed. The precise point of the collapse was directly beneath an old brick-lined construction shaft, the contents of which fell into the space below. The surrounding soil, which was a loose mixture of sand and clay, poured into the void and formed a large cavity underneath the foundations of two houses on Temple Drive. The houses, (numbers 22 and 24) suddenly collapsed into the ground killing five occupants; the end wall of another house fell outwards, though the occupants of this property were rescued. An official inquiry into the incident was conducted. A report compiled in 1954 concluded that timber shoring intended for temporary use during construction may have been left in place and had gradually degraded in the damp conditions; resulting in the tunnel's arch ring having to carry the full weight (roughly 200 tons) of wet sand in the filled-in construction shaft. It also ruled out mining activity as having played any attributable role in the collapse. Furthermore, that repeated recommendations by assistant chief works inspector H. Bradley for the tunnel's strengthening had been postponed, partially due to questions over the line's potential singling or closure, as well as restrictive funding available for such works. Aftermath The collapsed tunnel was determined to be in such a condition, particularly in regards to its brickwork, that extensive, and costly, remedial works would have been necessary to render it usable to rail traffic once again. Thus, decision makers quickly came to favour its permanent closure. Despite this, emergency reinforcement measures were carried out. Several years following the collapse, it was decided to fill in the tunnel using spoil and other waste materials produced by one of the nearby collieries. As a result of this infilling, the structure's portals are both buried and cannot be seen, however the route of the railway can still be made out by cuttings and embankments, especially when viewed on an aerial map. During the 2010s, civil engineering company M & J Drilling were contracted to stabilise the Clifton Hall Tunnel by grouting compromised sections. To support this activity, a comprehensive 3D subsurface laser scan survey was performed by Geoterra to ascertain the specifics and condition of the tunnel, which was accessed via a series of 100mm vertical shafts which were bored from the surface. Following the infilling of voids, further remedial work was undertaken. References Citations Bibliography