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
Grand Junction Canal at the rate of two guineas (£2/2s or two pounds and ten pence in decimalised currency) per day plus half a guinea (10s/6d or decimal £0.525) expenses. At the north end, there were problems with the construction of Blisworth Tunnel: quicksand was encountered, and errors made in alignment which meant that the tunnel had a pronounced wiggle. With the opening of Braunston Tunnel, the line was open from the Oxford Canal through to Weedon Bec in June 1796. However, Blisworth Tunnel continued to cause problems, collapsing in January 1796. The canal was opened from Braunston to Blisworth in 1797. The