|The Construction and Works of the Highland
Railway by Joseph Mitchell, F.R.S.E., F.R.S., C.E.
Page 1 of 4
|What follows is a transcript of a paper
read before the British Association at Dundee, in September, 1867. The original
document (National Archives of Scotland, reference BR/HR/4/100) is typescript
but has faded and is almost illegible in places. This transcript is an abridged
version of the paper. References to many individual bridges and other engineering
works have been excluded. The technical drawings, alluded to by the author,
are not extant among the records of the Highland Railway Company held by
the National Archives of Scotland.
The Construction and Works of the Highland Railway,
This title represents the union of several Companies in the north of Scotland, amalgamated three years ago under the name of the Highland Railway Company. The works consist of a main line from a point near Perth, extending 117 miles to the town of Forres, and a baseline running nearly at right angles to the other, extending westwards from the town of Keith by Elgin and Forres along the shores of the Moray Firth to Inverness, and thence along the Beauly, Dingwall and Dornoch Firths, northwards to Bonarbridge, measuring from Keith to Inverness 55 Miles, and from Inverness to Bonarbridge 58 miles, and making together a baseline of 113. These railways traverse the northern part of Perthshire, and are the main lines of communication through part of Banffshire and the counties of Inverness, Nairn, Moray and Ross, the whole including three branches - two to the ports of Burghhead and Findhorn in Morayshire, and the other to the village of Aberfeldy in Perthshire - and extending to 246 miles in length.
The country is fertile and comparatively flat for a distance of about 40 miles north of Perth, and also along the shores of the Moray, Dingwall and Dornoch Firths; but between Perthshire and Morayshire the line crosses two ranges of the Grampian Mountains, the one separating the valley of the Tay from that of the Spey, and the northern range separating the Spey from the valleys of the Findhorn. The large rivers which drain these mountain-regions debouch into the Tay, the Moray, the Dingwall and the Dornoch Firths. As the railway in most cases crosses those rivers near the sea, bridges of considerable magnitude are required. Besides the crossing of these rivers, other difficulties of a formidable character arose in crossing the mountains at so great an elevation, and in passing the rocky and precipitous defiles through which portions of the line had to run.
The northern counties traversed by these railways, except along the shores of the Firths are chiefly pastoral, exporting large numbers of sheep and cattle. The fisheries also are on an extensive scale; besides the salmon fisheries in the rivers, the annual take of white fish in the Moray First amounts to about 60,000 tons.
The object of the promoters, therefore, was to sweep the fertile shores of the Moray Firth, and to send the produce of the country by the most direct route to Perth, across the mountains, thus saving a detour by Aberdeen of nearly 60 miles. In laying out the main line and crossing the Grampians between Perth and Forres, long and steep inclines could not be avoided, but there is no steeper gradient than 1 in 70 throughout. The line to Blair, 36 miles from Perth, rises only 443 feet above the level of the sea, but from Blair to the summit of the southern range of the Grampians, a distance of 17 miles, the line rises 1045 feet, making the extreme summit of 1488 feet above the sea. In this distance there are gradients for 10 continuous miles of 1 in 72 and 1 in 70, and in the remaining 7 miles the inclines vary from 1 in 78 to 1 in 110. After passing this summit the line descends into the valley of the Spey, falling 747 feet in 18 miles, the steepest gradient being 1 in 80. On crossing the Spey, the line is comparatively level for a distance of 24 miles, when it again ascends by gradients of 1 in 84, 80 and 100, in order to pass the northern ridge which separates the valley of the Spey from that of the Findhorn. This summit is 1046 feet above sea-level. It afterwards descends to Forres (the point of the junction with the base-line) by gradients, the steepest of which are 1 in 70 for 8 miles, and 1 in 76 for 4 miles.