To return to a description of my line, there are on it three tunnels, two bridges, and a viaduct 91 feet long and 20 feet high. The latter was erected in 1878, as an improvement upon one at Aldershot, put up by a gentleman who induced the War Office to sanction a short experimental line for army transport upon a hopelessly inconvenient and ridiculous plan.
My structure is of pitch pine, and stood for 16 years without repair. It is a trestle bridge, the trestles being so designed that each member is a multiple of the height. The roadway is carried on four timbers; formerly, for a 8 ton engine, 11 in. deep and 8 in. wide; now, for one of 5 tons, 13 in. deep and 3½ in. wide. These are bolted together in pairs, one pair under each rail, the two being kept parallel by stretchers and through bolts at every 5 feet. In each pair the timbers break joint with one another on alternate trestles, the latter being 15 ft. apart, and each timber 30 ft. long. The advantages of this arrangement are two-fold, the timbers can be run forward from trestle to trestle as the work advances without scaffolding or lifting tackle, and, should one trestle sink out of line, the continuity of the upper work checks it, and obviates the dangerous “dog legs” to be almost invariably observed in this class of bridge. The original cost with the lighter timbers was £30, including every item of expenditure—equal to £1 per yard. The average height is 15 ft. The details are arranged to require but little skilled labour, the connections being made entirely by bolts and cast angle-plates. Two carpenters, in five days framed the five trestles including cutting the timber to length; and in three more days, with the assistance of three labourers, the whole was erected and the rails laid ready for traffic. A platform and railing were, however, subsequently added for the convenience of foot passengers, thus materially increasing the cost. When rebuilt in 1894 with stronger timbers, the original trestles were retained.
Where the line crosses field-fences a dyke is dug about 5 to 6 ft. square and 3 ft. deep, across which the rails are carried on two narrow girders, thus effectually preventing the passage of cattle, and avoiding both the delay of gates and the expense of side fencing.