Blea Moor Tunnel is a 2,629 yd (2,404 m) railway tunnel located between Ribblehead Viaduct and Dent railway station in England. It is the longest tunnel on the Settle-Carlisle Line, being almost twice as long as the second longest tunnel, Rise Hill Tunnel. Built by the Midland Railway, it took more than four years to complete, passes some 500 feet below the moor after which it was named, and was built with the aid of seven separate construction shafts sunk from the moor above. This permitted sixteen separate gangs of workers to be used during construction (one from each open end and two from the foot of each of the shafts). Four of these were subsequently filled in but three were retained for ventilation purposes and are still used as such today (with occasional ice accumulation problems: