EXTRAORDINARY BRIDGEBUILDING FEAT.

New Zealand Herald, Volume XXXIII, Issue 10037, 25 January 1896, Page 2 (Supplement)

EXTRAORDINARY BRIDGEBUILDING FEAT.

WHAT CAN BE PONS IN ELEVEN

HOURS, A WQHK of considerable interest as illustrating what can be done iii the way of rapid bridge construction was carried out (guys the Times) 011 the Great Eastern Railway at Ely, on a recent Monday. The Cutter Bridge, wliioh passed over the Ouee at Ely, was an old timber and cast-iron girder structure, which was put up in 1845, but was not considered equal to the heavier rolling stock of the present day. It had, therefore, been decided to substitute for it a bridge of wrought-iron girders, and having, 100, a single span across the river, on brick abutments, in space of the three spans and wooden piles of the old bridge. The problem that engineers and contractors set themselves to solve was how to pub the one bridge in place of the other with the least possible interference with any of the ordinary trains, whether passengers or goods, the point in question being one of the busiest on the company's system. The first part of the programme to be carried out consisted in the construction of the new bridge on temporary staging on one side of tlio line, parallel with and clear of the existing bridge, so that it would be quite ready for placing in position as soon as the latter was taken away. This was done, and 011 Saturday the new bridge, complete in every respect, including the lines of the permanent way thereon, was to be seen standing alongside the main line in readiness for t.Tie work on Sunday. The ends of the main girders were supported on small "trolleys," and each of the."e worked on a rail placed on longitudinal timber 011 the top of the temporary staging, so as to allow of the new structure being eventually drawn into position. At ten minutes past one on Sunday morning operations were begun. In ten minutes the first rail on the up line had been removod, and in another ten minutes the first girder was being carried off by two locomotive steam cranes working on the down line. The scene was illuminated by powerful Wells' lights, and girder after girder was carried off, steadily increasing the gap. The wooden piles which had supported the girder? were sawn through above water level, and the "crowns" carried off by the cranes, the lower portions being left to bo " drawn" on a future occasion. At last the up line and the greater portion of each of the particular piles on which it had rested had been cleared right away, leaving only the down line and its supports standing. Then came the most interesting feature of the morning's work-the "traversing" or drawing sideways of the new bridge, so that it would occupy (until the whole of the old bridge had been removed) the place where the up line had formerly stood. This traversing was done by means of two ropes worked by winches, and, although the massive structure weighed, including rails and timber, something like I*2o tons, it was drawn into its half-way position -a distance of fifteen feet—within a minute or two over half ah hour. By this time it was nearly six o'clock in the morning, and the actual time taken by the operation referred to was only about three and a half hours. Work was ro<umed at noon, and the worker?, about forty in number, proceeded to clear away the down line. The now bridge was then brought into position, for the remainder of the distance, in half un hour; the connections between the rails and with the abutments were completed, and at eight o'clock in the evening the express from Norwich to London passed safely over the new bridge. The substitution of the new bridge for the old one had taken about eleven hours' actual working, and had involved scarcely four hours' interruption of traffii).