Grand Junction Canal Nene at Northampton, to the turnpike road at Old Stratford (north-west of the modern Milton Keynes), and to Watford in Hertfordshire: those to Daventry and Watford were not built. The branch to Old Stratford was amended before it was built (see below). The branch to Northampton was delayed as the plans of the Leicestershire and Northamptonshire Union Canal to reach Northampton and thus join with the Grand Junction came to nothing. The link to Northampton was made by a tramroad transferred from Blisworth Tunnel, with the 5-mile (8-kilometre) canal from Gayton being opened in 1815. The link to Leicester was
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