The Kilsby Tunnel is a railway tunnel on the West Coast Main Line in England, near the village of Kilsby in Northamptonshire, roughly 5 miles (8 km) southeast of Rugby. It is 2,423 yards (2,216 m) long. The tunnel had atypically large ventilation shafts, because of a lack of experience as to how much ventilation would be needed for steam locomotives to pass through. On opening in 1838, the tunnel was single track and in 1879, double-track was laid. In March 1987, Kilsby Tunnel portals and its two ventilation shafts were given listed status.