The maps and pictures on this page show material related to Tower Subway. The Tower Subway is a tunnel beneath the River Thames in central London, between Tower Hill on the north side of the river and Vine Lane (off Tooley Street) on the south. In 1869 a circular tunnel was dug through the London clay using a wrought iron shield, a method that had been patented in 1864 by Peter W. Barlow. A gauge railway was laid in the tunnel and from August 1870 a cable-hauled wooden carriage conveyed passengers from one end to the other. This was uneconomic and the company went bankrupt by the end of the year. The tunnel was converted to pedestrian use and one million people a year crossed under the river, paying a toll of d. When the toll-free Tower Bridge opened in 1894 this caused a drop in income and the tunnel closed in 1898, after being sold to the London Hydraulic Power Company. The tunnel today is used for water mains.
In 1864 Peter Barlow patented a method of tunnelling using a circular wrought iron or steel shield and filling the gap between the tunnel lining with lime or cement to prevent settling of the ground above. He published a pamphlet in 1867 suggesting a network of tunnels with cars carrying up to 12 people. In 1868 authority was obtained for a tunnel under the Thames between Great Tower Hill and Pickle Herring Stairs near Vine Street (now Vine Lane), but there was a delay finding a contractor due to recent experiences with the Thames Tunnel until his former pupil James Henry Greathead tendered for £9,400.
Work began in February 1869 with the boring of entrance shafts, deep on the north bank and deep on the south bank. The tunnelling itself started in April and, using the circular shield, a tunnel long was dug with a diameter of, a maximum of below the high-water level. This was bored through a stable layer of the London clay that lay below the river bed, below the soft alluvial deposits that had plagued the construction by Brunel of the earlier Thames Tunnel. This, combined with the simpler nature of the project – the excavation face was only one twentieth that of the Thames Tunnel – enabled faster progress. Screw jacks drove the shield forward at a rate of each week. The under-river section was dug in fourteen weeks and the tunnel completed in December.