The permanent way was bedded upon Portland cement concrete, composed of twelve parts of gravel to one of cement. The upper surface of the concrete was carefully formed by means of a template, to fit the ribs or flanges on the underside of the cast iron templates. A modification, was the disuse of templates, with the plates simply hammered down with wooden mauls on the wet concrete. In this way, the latter were so firmly fixed in place that no spiking down was required, nor any connection between adjoining plates. Indeed a plate may break into small pieces, yet remain quite serviceable and level.
Originally, blocks of creosoted fir or hardwood, 11in x 5in x 4.5in, were spiked down to them at the corners by 1/2in spikes, in such a way as to connect adjoining plates, but this precaution was found unnecessary,and was abandoned. Originally, the plates for the ordinary straight parts of the line measured 6ft x 2ft 8in, latterly they were cast in 9ft lengths. The plates were procured from Woolwich Arsenal, where they were cast exclusively from obselete shot and shell.
The thickness was 1.5in, and the upper surface was chequred, to afford foot-hold for horses. The horse track proper was however of granite and lay between the two lines of plates. The groves which received the flanges of the wheels were 1.5in wide and of the same depth. Two longitudinal ribs, 4.5in wide and projecting 1.5in were formed on the underside of the plate, which was further strengthened by a transverse rib 5in from each end.
The distance between the outer edges of the two slots, which in reality constitutes the gauge, was 1ft 6in. The plates were set 2ft 5.5in apart, giving a "6-foot way" of about 3ft 7in. The space between was pitched with "half sovereign" granite pitching, outside, the plates was the usual granite pitching of dockyard roadways, 9in x 4in, the first row or two resting on concrete foundations, to prevent sinking, and consequent exposure of the edge of the templates.
A section of Narrow Gauge track Platework on display at the Historic Dockyard, Chatham
©N Short 2011