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
Indigo Tunnel of the parallel Baltimore and Ohio railroad line on the opposite side of the Potomac River. The tunnel was acquired by the National Park Service in 1980 and became part of Chesapeake and Ohio Canal National Historical Park. The Park Service has identified bat colonies living in the tunnel and has closed the tunnel to the public in order to protect the colonies. Indigo Tunnel Indigo Tunnel is an abandoned railroad tunnel in Allegany County, Maryland, located about east of Little Orleans. Built by the Western Maryland Railway (WM) in 1904, Indigo was the company's longest tunnel. It was part