PROGRESS OF THE SOUTHERN TRUNK RAILWAY.

Tuapeka Times, Volume V, Issue 243, 26 September 1872, Page 6

PROGRESS OF THE SOUTHERN TRUNK RAILWAY.

On Thursday, Mr W. N. Blair, C.E., District Engineer, courteously accompanied us over that portion of the Southern Trunk Railway now so rapidly advancing to completion, and we are thus enabled to give our readers a slight sketch of what has been accomplished. There is no necessity for lengthened remarks concerning that portion of the line near Dunedin A quarter of an hour s work will put it in thepowerof any one who is curious iv such matters to view it thems- lyes. To most of the younger branches of our population, however, a railway is a something of which they can only form an idea from drawings, and the high embankments thrown ac-.oss valleys, apart from their use, seem but very unsightly objects. Yet these are necessary, in order to attain a line of road sufficiently horizontal to travel upon with case and safety. Nor is even the embankment itself without interest. The skill of the engineer is severely tested many times in theadoptioa of means to render these artificial hills secure. They muat be firm enough to carry the weight of the train, aggravated by vibration, without breaking; and wherever there is a gathering of water, means must be provided for its flowing away rapidly and f reeh , lest percolating through the lower part « f the embankment, it may wear itself a channel, and destroy the work. The culverts at different points of the line are to guard against this. They are more than ordinarily carefully framed, and are of ample dimensions to carry off any storm water that nr ay suddenly require a passage. Those we have examined are of blue-stone. The masonry is good, and the arches well turned. At Caversham the railway crosses the main road. The point chosen affords sufficient height for waggons carrying any description of load to pass clear of the underside of the bridge. It is laid upon iron girders resting upon well built piers of bluestone. The opening is twenty-one feet wide, and it crosses the road at an augle, thus making what is technically termed a skew bridge. We believe such a mode of construction is peculiar to modern times, aud is one of the outgrowths of railway formation. Clever as were the Romans in forming viaducts and aqueducts, we do not think an instance has been found of such a plan of construction, which when first adopted somewhat puzzled the masons of the day in the turning of the arches. The bridge at Caversham, however, presents no difficulty of that sort. It only requires the girders on one side to be slightly longer than ou. the other. One interesting fact connected with- this and the other short bridges between the town and the tunnel is, that those I heavy girders were made by a Dunedin firm. Mr Sparrow supplied them, and they are substantial and of good workmanship. At ' present the bridges wear the appearance j of want of finish, but this will be obviated by i facing them with a balustrade, and they will then present a neat appearance. The severs and wet winter has proved the embankments, which may be now said to have settled down to their permanent level. Although on crossing a wide valley they preeent to a distant spectator only the appearance of a line, their width is realised by those who walk upon them. It . is very ample for a single line of rails, and the wide splay of the lower strata gives full assurance of the stability of the embankments. We believe the ! slopes will be sown with grasses and herbage, the intertwining of the roots of which forms lan efficient protection against atmospheric action. It is needless to particularise every cutting and every embankment traversed. They are so much like one another, as a rule, that, apart from the geological interest con. nected with the various strata in the cuttings, if one is described, a reader knows aIL On a railway, man's inventions are perhaps more generally interesting than geological appearances. A railway is man's mastery over natuval obstacles. There are many in.