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
Kilsby Tunnel presence of large amounts of quicksand; trial borings into the hill had not revealed any quicksand in the vicinity, but Stephenson had already made efforts to avoid any such an encounter being made. However, similar problems had previously been encountered during the construction of the nearby Blisworth tunnel on the Grand Union Canal only a few decades earlier. The problems that were posed by the quicksand, which was eventually revealed to be quite prevalent at tunnel level, were so severe that some considerations were allegedly made towards the abandonment of the shaft and restarting work afresh elsewhere; the resulting stress