Lithgow Zig Zag

The Lithgow Zig Zag was a zig zag railway built near Lithgow on the Great Western Railway of New South Wales in Australia which operated between 1870 and 1910, to overcome an otherwise insurmountable climb up the western side of the Blue Mountains. It is now used by the Zig Zag Railway, a narrow gauge tourist railway.

History

The original plan, by the newly-appointed Engineer-in-Charge, John Whitton, had been to build a 3 km tunnel, but this was beyond the resources of the state of New South Wales at the time. The zig zag alternative still required several short tunnels and some viaducts.

On the eastern side of the range, the first Blue Mountains Zig Zag (known as the Lapstone Zig Zag) opened near Glenbrook in 1867. It ascended Lapstone Hill on a gradient of 1:30 to 1:33 (~ 3 - 3.3%), which contoured up the side of the range with comparatively light earthworks.

By contrast, the Lithgow Zig Zag railway, built between 1866 and 1869, required much heavier engineering, including four large rock cuttings, three fine stone viaducts with 30-foot semi-circular arches (originally four were planned, but one was built as an embankment instead) and a short tunnel (three tunnels were planned, but two were daylighted during construction due to leaks, becoming two of the four cuttings mentioned above). In the descent of the middle road, the line dropped 101 feet between the reversing points, being part of the 550 foot descent from Clarence. The whole route had a ruling grade of 1:42 (~2.38%).

On Monday October 19, 1869 the Lithgow Zig Zag opened to traffic, completing the route over the Blue Mountains.

The Lithgow Zig Zag operated between 1870 and 1910. By then it had become an increasingly inefficient bottleneck owing to the growing traffic on the line between Lithgow and Sydney. It was eventually abandoned in 1910, replaced by the Ten-Tunnels Deviation, a double tracked route with a ruling grade of 1:50. This is still in heavy use as the Main West line to the central-west of NSW and ultimately the trans-Australia line to Perth today.

During World War II Glenbrook, Clarence and Zig Zag tunnels were used to store chemical weapons for the Royal Australian Air Force. Principally mustard gas and phosgene the chemical agents were housed in a variety of weapons from bombs to cylinders. The cache was disposed of after the war. [ [http://www.mustardgas.org/depots.htm Australian supervised ] ]

In 1975 it was decided to restore the Lithgow Zig Zag as a heritage railway, which operates as the Zig Zag Railway.

ee also

* Lapstone Zig Zag

References

Further reading

* Full Steam Across The Mountains - Phil Belbin & David Burke - Methuen Australia 1981