The possibilities of this scheme are not exhausted, as there remains to be mentioned the opening of railway communication across the river by a tunnel under the dam and of road communication by a roadway over the dam. These are clearly shown in the accompanying Figs. 4, 5 and 6.

The tunnel will be constructed in the foundation of the dam, and the road formed on the top of the dam, and provided with opening bridges across the locks.

A glance at a railway map will at once show the strategic value of the railway route thus opened up between the Midlands and the North, and Dover and the South Coast, avoiding the conjested London lines; also for national and military direct traffic between the Government arsenals and the Colchester and northern routes and depots. All the northern lines will thus have access by the Tilbury line to the continental routes.