Blisworth Tunnel was the only section unfinished. This was despite the tunnel having been under construction for seven years: the gap was filled by a temporary horse-drawn tramway over the top of the hill, with goods being transported from boat to wagon and back again. The tramway, built in 1801, was Northamptonshire's first railway. In March 1805, the tunnel was finally opened and the rails were used to connect the main line of the canal to the River Nene until the branch canal to Northampton was constructed. Until the 1870s travel through the tunnel was only achieved by men lying on their
Sapperton Canal Tunnel workmanship, as it had to be closed for ten weeks after only a year, while repairs were carried out. It was superseded as the longest canal tunnel in England in 1811 by the Huddersfield Narrow Canal's Standedge Tunnel, which was long when built, later extended to to accommodate the adjacent railway tunnel, and remains the highest, longest and deepest canal tunnel in Britain - though, unlike Sapperton, Standedge can only accommodate . Strood Tunnel on the Thames and Medway Canal was also longer at when it opened in 1824, but was cut in two in 1830 by opening out a