Location of the Railway

There is, however, one additional alignment advantage of a railway: its ability to reverse direction on a very narrow shelf cut into a mountainside, where the hairpin bend of a road would require a wider shelf for a reversing turn. Here it is useful to remember that manoeuvering a 20-bullock dray team under conditions of maximum traction or braking, through a small-radius 180 degree turn, posed problems every bit as formidable as that facing a semi trailer truckie on some of our mountain pass roads today.

It is difficult to identify the earliest applications of the main line railway zig-zag solution to gaining elevation by a series of directional reversals on a mountainside. In India the first flat section of the Great Indian Peninsula Railway from Bombay to Kalyan was opened in 1853, two years before the Sydney railway to Parramatta.[4] The respective transmontaine extensions up the Bhor Ghat towards Poona and from Penrith westward over the Blue Mountains, would have been surveyed around the same time. Probably as a result of the flow of information which was conveyed through the mail steamer link from England to Australia the work in Bombay would have been recognised. It is therefore difficult at this distance to say who thought of the zig-zag idea first. The original 1867 Bhor Ghat alignment contained one such reversal (on a projecting peninsula of high ground). John Whitton's use in Australia of a double-reversal zig-zag solution on a one in thirty three grade to climb the steep eastern escarpment of the Blue Mountains at Lapstone, and to descend at one in forty/forty two into the western valley system at Lithgow, established himself as a major innovator in main line railway location.

John Whitton was also the great engineer of the central core of trunk railways in New South Wales. He also succeeded in engineering deep cuttings, sandstone viaducts and minimum tunnels. His work is still used to this day, although in the case of his two zig-zags, no longer by main line trains. The 'Great Zig-Zag' at Lithgow in particular was widely publicised in engineering circles and the plans may have been the inspiration of the American, Henry Meiggs, who built the world's largest and best known complex of railway zig-zags on the Central Railway of Peru in 1870 on an alignment surveyed by a European engineer. Another Australian zig-zag railway was established on a branch line to Kalamunda near Perth.

Australian Academy of Technological Sciences and Engineering