The Kilsby Tunnel is a railway tunnel on the West Coast Main Line railway in England. It was designed and engineered by Robert Stephenson.The tunnel is located near the village of Kilsby in Northamptonshire roughly 5 miles (8 km) south-east of Rugby and is 2,432 yards (2,224 m) long.The tunnel was opened in 1838 as a part of the London and Birmingham Railway.