Monument record MHG2871 - Aultnaslanach Viaduct

NH73SE 16 7601 3494

(Name cited as Aultnaslanash and location as NH 759 349). Opened 1897 by the Highland Rly. A 5-span wooden trestle bridge, the only one of its kind on a main-line railway in Scotland. Retained owing to the difficulty of securing foundations for a steel or masonry bridge.
J R Hume 1977.

This wooden trestle bridge carries the single-track Aviemore-Inverness railway across the Allt Creag Bheithen just N of the former station at Moy (NH73SE 19). This line was opened by the Highland Railway Company in 1897, and the bridge is now the only surviving structure of its type on a main-line railway in Scotland, possibly in Britain.
The bridge is 132ft 7ins (40.41m) in length by 28ft 6ins (8.69m) in width with raking shores spreading the width to 60ft (18.29m) overall. There are five spans, varying between 24ft 4in (7.42m) and 25ft 1in (7.65m) in length centre to centre, and the decking stands 27ft 9in (8.46m) above the normal water-line of the burn.
Compared with the elaborate structures of this kind erected by I K Brunel in England and those on North American railroads, this bridge is of modest trestle frame and multiple prop-and-beam construction, employing heavy pitch-pine baulks with iron-clad joints. The sectional corrugated-iron deck is carried on a series of six longitudinal girders, each made up of coupled baulks mounted on top of the other. There are six trestle bents, the two end ones being set within the embankments. Each of the four central frames is composed of six upright posts driven into the ground like piles and joined together by runners, beam-stiffeners and, at the head, a transverse beam. The main structural components are braced laterally by raking shores, and longitudinally by an elaborate system of raking struts associated with the main girders and a lower straining-beam.
G D Hay and G P Stell 1986.

This bridge carries the revised or 'direct' route of the Aviemore - Inverness portion of the Perth - Inverness (main) line of the former Highland Rly. across the Allt Creag Bheithen. It remains in regular use by passenger traffic.
Information from RCAHMS (RJCM), 8 May 1998.

This site has only been partially upgraded for SCRAN. For full details, please consult the Architecture Catalogues for Inverness District.
March 1998