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Deptford Wharf Branch Railway (DPW). Lifting Bridge near New Cross station, carrying the LBSCR branch over the Grand Surrey Canal. 1849-50

Grid Ref: TQ 3575 7796. The "vertical lift bridge" bridge (Map Ref TQ 35745 77965) consisted of a rectangular platform of timber, carrying on one side the railway line and, on the other, a roadway for carts, and resting, when down, upon piles driven into a bed of hard gravel. The platform was suspended at the four corners by wire ropes, which passed over pulleys fixed on four pairs of cast- iron standards (also supported on piles), and then attached to drums, each pair of which were keyed on to the same horizontal shaft, lying a few inches under the rail and road level. Upon the same shafts were also fixed six other drums of equal diameter, carrying, upon coils of wire rope, balance weights, intended to assist in raising the platform , and which moved up and down cast-iron cylinders, or wells prepared to receive them. Motion was given to one end of each shaft, by means of simple hand-gearing, consisting of a train of wheels and pinions, by which the power was multiplied twenty-six times. The outside width of the platform was 23 feet, equally divided between the railway and the road, and the length was 35 feet; but the clear waterway in the canal was only 21 feet on the square, the additional length arising from the direction of the line being slightly askew to the canal, and from the necessity of leaving a clear width of 54 feet for a towing-path on the north bank. The level of the rails upon the bridge, when down, was 4 feet 2½ inches above the highest water-line, and the platform was capable of being raised so as to give a clear headway of 9 feet 6 inches below the tension rods, which was the height required by the Act for the fixed bridge erected over the same canal, at the second crossing near Deptford. The weight of the entire platform, with all the fittings complete, was about 12 tons, when the timber was dry. The drawing is included in the paper describing the bridge, its design, and construction, by Robert Jacomb Hood, M.I.C.E., (from which the above information is extracted), and contained in the Proceedings of the Institution of Civil Engineers for the 1849-50 Session (page 303). It is clear that the bridge underwent a number of structural changes during its life, including that, by the time the area was surveyed in 1868, the roadway section had gone and the bridge comprised just that for a single railway line. However, alongside but separate, was a second lifting bridge whose purpose is not certain but which appears to be a roadway crossing. This may be the arrangement in the photograph we have for the bridge.