PROGRESS OF THE SOUTHERN TRUNK RAILWAY.

Evening Star, Issue 2989, 17 September 1872, Page 2

PROGRESS OF THE SOUTHERN TRUNK RAILWAY.

No. 1. 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 thepower of any one who is curious in such matters to view it themselves. 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 across 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 ease and safety. Nor is even the embankment itself without interest. The skill of the engineer is severely tested many times in the adoption of means to render these artificial hills secure. They must 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 freeh, lest percolating through the lower part of 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 may suddenly require a passage. Those wo 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 descrip! ion of load to pass clear of the underside of the bridge, lb is laid upon iron gird .is resting upon well built piers of bluestone. The opening is twenty-one feet wide, and it crosses the road at an angle, 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 aud aqueducts, we do not think au 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 on the other. One interesting fact connected with Ibis and the other short bridges between the town and the tunnel is, that those heavy girders were made by a Dunedin firm. Mr Sparrow supplied them, aud they are substantial and of good workmanship. At present the bridges wear the appearance of want of finish, but this will be obviated by facing them with a balustrade, and they will then present a neat appearance. The severe aud wet winter has proved Die embankments, which may be now said to have settled down to their permanent level. Although on crossing a wide valley they present to a distant spectator only the appearance of a line, their width is iodised by those who walk upon them. It is very ample for a single line Of rails, and the wide splay of tbe lower strata gives full assurance of the stability of fchj embankments. We believe the slopes will be sown with grasses and herbage, the intertwining of the roots of which forms an 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 connected with the various strata in the cuttings, if one is described, a reader knows all. Ou a railway, man’s inventions are perhaps more generally interesting than geological appearances. A railway is man s mastery over natural obstacles. There are many ingenious contrivances, too, for the couservation of the rights of persons owning property on the line, and the protection of human aud animal life. Where a private road has been interfered with another has been made, and we believe in every instance the change has been beneficial—bad roads have been replaced with good, and steep gradients with easy ones. Wc believe, notwithstanding this, there arc grumblers ; but what will not such men grumble at ? Occasionally a district road crosses the railway on a level. In America tli is is considered of no nioinant, and no precautions are taken to avoid trespass on theline. We Britons do not consider such inducement to self-reliance advisable, and accordingly gates are placed which are so arranged that when they bar the road the railway line is open, and when they prevent access to the railway the road is open, it is a simple contrivance to guard against cattle straying, Tim only fear is that when so much is done to prevent damage to other people’s property they will not take the trouble to do anything for themselves, but will neglect the best safeguard—preventing their cattle wander-in-r. la one or two instances a novel, plan ha's been adopted of what is termed “a Yankee crossing.” It simply consists of a wide trench containing water across the railway on each side of the distiict road. The trains will pass over these on short girders, which nohorsa or cow would be mountebank enough to walk upon for the sake of gaining access to ground on which there is no food. Perhaps a cow might plant herself across the rails, aud take her stand in defiance of an approaching train, when, as Georg j Stephenson said, it would “be varry bad for the coo.” Proceedingouwards, we came at length to a deep cutting through easilyworked sandstone, which continued until we reached the entrance to the tunnel. We here met one of the brothers Mackenzie, w ho have successfully prosecuted the work as sub-contractors under Mr j. femyth. He politely placed an empty waggon at the disposal of the party; but, prior to entering the tunnel, Mr Blair gave us a highly mteresting detail of the plans adopted to secure the strictest accuracy in the direction of the tunnel. The necessity for this is obvious when it is considered that it is 946

yards in length, and that the work is carried on at both ends simultaneously. If, then, an error in the direction of only an eighth of an inch had been made at the beginning at one end, and continue il to one half the distance, instead of meeting in the centre in a continuous line, one half would diverge five feet from the direction of the other. The nicest accuracy is therefore required. We need not trouble our readers with anything beyond a general idea of the plans adopted. The difficulties in the way of accuracy aro manifold, ifirst, there is a high hill between the two points of starting; secondly, when a series of standards were set up, determining an exactly straight line over the mountain, it is necessary that the tunnel should be made exactly in the same direction through it; thirdly, the tunnel is dark, and it depends very much upon the state of the air within it whether an accurate series of observations can be made for their truth depends upon whether a light can be seen suspended from the root a its centre. The plumb line within a hut, sheltered fiom the wind outside the tunnel, and a light suspended, as we have said, from the centre of the roof inside, are the simple means adopted. The eyel presents less difficulty as it can be determined by the usual appliances. Mounting a waggon, or rather we might say a couple of waggons for an inch and a-half plank was placed Wthwise on two to form a seat, we made a St for the tunnel from the point at which the “spoil” is deposited. The sandstone Jock towered high above our heads, presentrocic . : d eveu face, excepting at aand was ia p h ave passed since it rightly, fo,a , .1 1 eg crop ou t from their 5 "0? tVmighty changes aeep grave v ™ conv ey ance of thfspS'from thJ tunnel, two lines of rails were drawn g ftt t } ie distance Kariy 1 «« hntw yards, appeared to be 6 tared'atrort Chalmers, in Wasting, renders a sunplv of fresh air necessary to the health and comfort of the workmen. This is secured by a very effective but simple arrangement What we saw in the tunnel must ffirm the subject of a separate article.

A curious and romantic bequest has just hi made to a servant in Jersey, the circumstanees of which are as twenty years ago the daughter of - P Con/gentleman in wifh her father’s coachman, a man namtu Smith and married him. ami was therefm-e STS? tatatd; been earning some 12s per week, was employed digging potatoes in his garden that his wife’s father was dead and had him property valued at L 20,000.

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