Main Street Tunnel technique, whereby the tunnel was excavated, the concrete poured, and the structure buried, on top of which the canal channel was built. This avoided costly boring beneath an active waterway; the structure cost C$11 million. This price was split 50–50 between Transport Canada and the St. Lawrence Seaway Authority. The tunnel opened with a parade featuring the Welland Police pipe band and various officials on the morning of May 20, 1972. Main Street Tunnel The Main Street Tunnel, located in Welland, Ontario, Canada, is an underwater tunnel, carrying Niagara Road 27 and the unsigned designation of Highway 7146 under the
Severn Tunnel Severn between Sharpness and Lydney opened to traffic during 1879. On 22 October 1884 laying the double tracks in the tunnel started. On 18 April 1885, the final brick was placed in the tunnel's lining. The tunnel was horse shoe-shaped in cross-section with a concave floor, its height was 6.1 meters above the rails with a maximum width of 7.9 meters. An enclosed 533mm high drainage channel, in the form of an upturned semi-circular tunnel, is built onto the tunnel invert, 1.4 meters below the rails. Around 76.4 million bricks were used in the tunnel's construction. The brickwork is between