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
Pennsylvania Canal Tunnel Pennsylvania Canal Tunnel The Pennsylvania Canal Tunnel was the Pittsburgh terminus of the Pennsylvania Main Line of Public Works, a transportation system that involved other early tunnels. Construction was authorized February 8, 1827, and the tunnel was completed November 10, 1829. The canal crossed the Allegheny River on a covered bridge aqueduct, later replaced by John A. Roebling's first suspension bridge, the Allegheny Aqueduct., the canal traveled underground through most of downtown Pittsburgh, under Grant's Hill, to end in a lock leading to the Monongahela River. The original plan was to connect with the C&O canal at the Monongahela River,