Volume Twelve - Pre-Victorian to the Present Day - further aspects - Report upon Penarth Dock - 1984 . . .

2.4.3 - Subway

In 1896 Parliament authorised the building of a subway under the River Ely to link Penarth Dock with the Penarth Tidal Harbour. The contract for the work was awarded to Mr. Thomas Taylor of Pontypridd and work was started on June 5th 1896 with the first cast-iron ring for the walls of the subway being positioned on July 5th 1897.

Construction was particularly difficult due to the fact that the bed of the River Ely consisted of alluvial clay and occasional sand deposits. In fact the river flooded the subway twice during it's construction despite the use of compressed air to prevent this. Originally the subway was intended for vehicle traffic but due to difficulty in construction and rising cost of the work the subway was eventually for foot passengers only.

The subway was reached by an inclined plane on either side of the river leading to the main part of the subway some 50 feet below high water. The total length was 1,250 feet with an internal diameter of 10 feet. The footway itself was 8 feet 10 inches wide with the remaining space being taken up by four pipes carrying hydraulic power, gas and water from Penarth Dock to the tidal harbour.

The gradients at each end were 1 in 9 and under the river they were connected by a vertical curve 800 feet radius. For 817 feet of it's commencement the subway took a straight course; for the succeeding 267 feet it ran on a curve of 205 feet; and after that it was straight to the rising plane at the end on the opposite side. To minimise the danger of the subway flooding several hundred tons of clay were laid over the line of the subway on the river bed.

By 1899 two-thirds of the work had been completed and the subway was finally opened for use on 11th May 1900.

Figure 4 - Details of the subway under the River Ely.