Blisworth Tunnel sections lined with pre-cast concrete rings. It was also used to test out the materials that were later used on the Channel Tunnel. An unused ring is on display near the south portal. Blisworth Tunnel Blisworth Tunnel is a canal tunnel on the Grand Union Canal in Northamptonshire, England, between the villages of Stoke Bruerne at the southern end and Blisworth at the northern end. The northern end is about from the northern end of the Grand Junction Canal at Braunston, Northamptonshire and the southern end about . At 3,076 yards (2,813m) long it is the third-longest navigable canal tunnel
Dudley Tunnel the tunnel pass through a dolerite known locally as Rowley Rag; and through Coal Measures rocks. The Netherton Tunnel follows a parallel route 1½ miles to the south east; it is much larger and has twin towpaths running through it. It was built to ease congestion in the Dudley Tunnel. Dudley Tunnel Dudley Tunnel is a canal tunnel on the Dudley Canal Line No 1, England. At about long, it is now the second longest canal tunnel on the UK canal network today. (Standedge Tunnel is the longest, at , and the Higham and Strood tunnel is now rail only).