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The Great Zig Zag at Lithgow when it was part of the Main Western railway line. Top road and No. 1 viaduct are in the foreground, middle road with Viaducts Nos. 2 and 3 is in the centre, and bottom road is at the right. Photo: Powerhouse Museum Collection. This image is in the public domain.

The Great Zig Zag. Photo: Powerhouse Museum Collection, Wikimedia Commons. This image is in the public domain.

Zig Zag Railway

David Matheson

 28 May 2023

The first passenger railway in New South Wales opened to the public between Sydney and Parramatta in September 1855. During its planning and construction it was envisaged that railways would be extended into the interior of the state. An aim of the Sydney Railway Company, which began construction of the first line, was for railways to reach Goulburn and Bathurst. The railway to the west reached Penrith, 55 km from Sydney, in 1863, but progress further west faced the barriers of the Nepean River and the Blue Mountains.


John Whitton was the Engineer-in-Chief of the New South Wales railways from 1857 to 1890. He was responsible for the construction of new lines and designed the railway across the Blue Mountains. In 1867 the railway was opened between Penrith and Weatherboard (now Wentworth Falls). It included a bridge across the Nepean River and a zig zag at Lapstone, near the bottom of the Blue Mountains. A train climbing the Lapstone Zig Zag would stop at Bottom Points and change direction until it reached Top Points. The train would then change directions again, continuing forwards once more towards its destination. Lapstone Zig Zag was in operation for 25 years until it was bypassed by a tunnel in 1892.



The railway was extended from Weatherboard to Mount Victoria in 1868 and to Bowenfels in 1869. Mount Victoria is near the top of the Blue Mountains at an altitude of 1044 metres above sea level, and construction of the line beyond here required a descent on the far side of the Blue Mountains. John Whitton again turned to the use of a zig zag. The Great Zig Zag, or Lithgow Zig Zag, was much larger than the Lapstone Zig Zag, and was a major work of engineering. Construction commenced in August 1866, with the contract for the building work being awarded to Patrick Higgins. By January 1867 around 700 men were employed and No. 1 tunnel on the zig zag had been completed. On 5 January an explosive charge was detonated to remove 45,000 tons of rock. Further explosions were used later. Two workers were killed by a rockfall following an explosion on 20 August 1867. Workers lived in tents and endured temperatures that were often freezing in winter.


The completion date for the contract had been December 1868, but work was not complete by this time and an extension of six months to June 1869 was granted. However, work was still ongoing when this month was reached. Final works included the laying of track and the construction of buildings. The railway between Mount Victoria and Bowenfels, incorporating the Great Zig Zag, was opened on 18 October 1869.


Zig Zag features

There are two tunnels between Clarence and Lithgow. Clarence Tunnel is located a short distance west of Clarence station, and is 493 metres in length. No. 1 Tunnel (or Zig Zag Tunnel) is 69 metres in length and is on the middle road of the Great Zig Zag. Another tunnel was planned for the middle road of the zig zag, but No. 2 tunnel was opened out due to concerns that the rock above was unstable


There are three viaducts on the Great Zig Zag. No. 1 Viaduct is located on top road and is 82 metres in length. It has seven arches and a maximum height of 14 metres. No. 2 Viaduct is located on middle road between Top Points and Bottom Points and has a length of 101 metres. It has nine arches and a maximum height of 23 metres, making it the highest and longest of the three viaducts. No. 3 Viaduct is also on middle road between Top Points and Bottom Points and has a length of 91 metres. It has eight arches and a maximum height of nine metres.


Trains heading west descended the zig zag. Most of the Great Zig Zag has a gradient of 1 in 42 (2.4%), which is very steep for a main line. A stop would be made at Top Points to change direction, and then another stop was made at Bottom Points to change direction again. Clarence station, located on the approach to the zig zag from the Sydney end had an altitude of 1115 metres above sea level, the highest on the western railway. Lithgow station has an altitude of 920 metres, so trains traversing the section from Clarence to Lithgow descended a total of 195 metres in altitude.


The Great Zig Zag attracted considerable attention as a great work of engineering and construction. It attracted numerous tourists, who admired the features of the zig zag and the local scenery. Many considered it a site of world significance. The area was declared a public reserve in 1881 and was a popular picnic spot.


Bottom Points was the only location on the zig zag that was staffed upon opening. John McNab was a pointsman who assisted trains working through Bottom and Top Points. An additional siding was opened at Bottom Points in 1878, enabling trains to cross there. A siding was opened at Clarence in 1873, and then a station was opened there the following year. In 1890 the siding at Clarence became a crossing loop.


Following the opening of the railway to Bowenfels, industry developed in the Lithgow area, including four collieries, a copper smelter and an ironworks. Two small wooden platforms had been built in Lithgow, named Lithgow and Browns, but they were not officially recognised stations. The first official station in Lithgow was Eskbank, which opened in June 1874. Railway traffic grew and the line between Lithgow and the Bottom Points of the Great Zig Zag was duplicated in October 1880. Traffic density continued to increase, requiring the use of bank engines to assist trains working across the zig zag. Long trains often needed to be split and each portion was hauled separately before being combined again after climbing the zig zag. A crossing loop was opened at Edgecombe, located on the top road of the zig zag, on 29 October 1901. By the middle of 1907 an average of 20 goods trains and seven passenger trains were traversing the Great Zig Zag on a daily basis. Delays to trains were increasing as the zig zag was struggling to keep up with the number of trains. To improve train working an extension to the track was made at Bottom Points, while a new wing was put in place at Top Points, both of these works being completed in 1908.


Closure and re-opening

Eventually the zig zag was bypassed by a double-track deviation in 1910. The new route was known as the ‘Ten Tunnels Deviation’ because it included ten tunnels of varying lengths from 70 metres to 825 metres. Construction of the deviation commenced in June 1908 and it opened for traffic on 16 October 1910. The new route bypassed most of the zig zag but made use of the original bottom road, and is this route is still followed by the existing western line today. Passengers can see Bottom Points and the viaducts on the zig zag from the left side of trains heading west. Most of the deviation has a gradient of 1 in 90 (1.1%), although trains continued to negotiate the 1 in 42 (2.38%) section along the former bottom road. Assistant engines from Lithgow to Zig Zag enabled heavier train loads to be carried. The use of double tracks and avoiding the need for trains to change direction made travel times considerably faster. In 1957 the Blue Mountains railway line was electrified through to Lithgow and Bowenfels, while the Ten Tunnels section was upgraded with a lower floor and a concrete track bed to accommodate double-deck trains in the 1970s.


After its closure the tracks on the top and middle roads of the zig zag were removed. It continued to receive visitors as a popular tourist attraction and picnic location. Following the centenary of the opening of the zig zag in October 1969, momentum grew for the re-opening of the top and middle roads of the zig zag as a tourist railway with steam trains hauling services. A group of volunteers was formed, which eventually became the Zig Zag Railway, and work commenced. The restored track was laid to narrow (1067 mm) gauge, although the original track operational between 1869 and 1910 was standard (1435 mm) gauge. Narrow gauge locomotives and carriages were obtained from Queensland Railways and South Australian Railways. A depot was established at Bottom Points. On 18 October 1975 the middle road was opened for heritage train services. Passengers were able to drive along the top road to Top Points and make a steam train journey from Top Points to Bottom Points and return. Alternatively, passengers could catch a regular train and alight at Zig Zag platform, located at Bottom Points.


In 1988 the Zig Zag Railway was extended from Top Points to Clarence. Trains operated between Clarence and Bottom Points, changing direction at Top Points. The Zig Railway became a significant tourist attraction in the Blue Mountains. Tourist trains temporarily ceased operating in 2012, and in following years bushfires and floods caused the loss of numerous carriages and damage to infrastructure. Public services on the Zig Railway resumed on 27 May 2023.



Bayley, W A, Lithgow Zig Zag Railway, Locomotion Productions, Mount Victoria, 2000.

Forsyth, JH, How & why of station names, 2nd edn, State Rail Authority Archives Section, Sydney, 1982.

Langdon, M, Conquering the Blue Mountains, Eveleigh Press, Sydney, 2006.

‘Bell To Zig Zag Ten Tunnel Railway Deviation & Zig Zag Rail Corridor’, Office of Environment and Heritage,

     <>, accessed 20 April 2019>.

Wylie, RF & CC Singleton, ‘The railway crossing of the Blue Mountains, Part 6: Bell to Zig Zag’, Australian Railway Historical Society Bulletin, no.

     253, November 1958, pp. 165–78.

Zig Zag Railway <

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G23 Class locomotive No. 34 (renumbered 1412 in 1924) climbing the middle road of the Great Zig Zag. Photo: Wikimedia Commons.


Former Queensland AC16 class 2-8-2 locomotive 218A with train, Clarence, Zig Zag Railway, Lithgow, 16 October 2010.

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