Lithgow Zig Zag

The Great Zig Zag
Lithgow Zig Zag
Top, middle, and bottom parts of the Zig Zag railway
Locale	Western Blue Mountains, New South Wales
Coordinates	33°28′33″S 150°11′52″E / 33.475882°S 150.197875°E / -33.475882; 150.197875Coordinates: 33°28′33″S 150°11′52″E / 33.475882°S 150.197875°E / -33.475882; 150.197875
Commercial operations
Name	NSW Government Railways Great Western Railway
Built by	Patrick Higgins (contractor for NSWGR)
Original gauge	4 ft 8 1⁄2 in (1,435 mm)
Preserved operations
Operated by	Zig Zag Railway Cooperative (established 1972) as Zig Zag Railway
Stations	Clarence, Mt Sinai Halt, No1 Viaduct, Top Points, Cockerton, Bottom Points
Length	7 kilometres (4.3 mi)
Preserved gauge	3 ft 6 in (1,067 mm)
Commercial history
Opened	18 October 1869
Closed	16 October 1910 (bypassed by the Ten-Tunnels deviation)
Preservation history
Website
Zig Zag railway website

Lithgow Zig Zag routes
Legend
to Sydney Central Bell Dargans Deviation Junction Newnes Junction Newnes Junction(original) Newnes railway line Clarence Clarence(original) Summit Clarence Tunnel Mt Sinai Halt No. 1 Viaduct Ten Tunnels (on Main Western Line) Top Points No. 2 Viaduct No. 3 Viaduct Belmore (Zig Zag) Tunnel Bottom Points Bottom Points Depot Zig Zag Mileage 92.1 Junction Eskbank Lithgow to Dubbo and Bourke

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. The Lithgow Zig Zag is listed on the NSW State Heritage Register.

It is now used by the Zig Zag Railway, a narrow gauge tourist railway.

Construction

The original plan by the Engineer-in-Charge of New South Wales Government Railways, John Whitton, had been to build a 2-mile (3.2 km) tunnel. However, this was beyond the resources of the Colonial Government at the time. The zig zag alternative still required several short tunnels and some viaducts.^[1]

On the eastern side of the range, the Lapstone Zig Zag, also designed under the supervision of John Whitton, opened near Glenbrook in 1867. The Lapstone Zig Zag 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.^[2]

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 (9.1 m) 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 (31 m) between the reversing points, being part of the 550 feet (170 m) descent from Clarence. The whole route had a ruling grade of 1:42 (~2.38%).^[1]

Commercial operation and closure

On 19 October 1869 the first official train ran across the Lithgow Zig Zag to Bowenfels railway station, completing the route over the Blue Mountains. This event was heralded worldwide as an engineering marvel resulting in many organised sight-seeing parties from overseas to view it.^[1] According to NSW Planning Department documents, in international references, John Whitton is recognised as one of approximately twenty of the greatest railway civil engineers in the first century of world railway construction. The achievement of his crossings of the Great Divide was superlative at the time and in terms of British railway civil engineering was only exceeded by the difficult crossing of the Indian Ghats.^[1]

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. The Top Points were also too short. In 1901 a goods engine burst through the buffer stops located at the top 'wing' and almost fell into the valley below. To alleviate the congestion until a new deviation opened the 'top' and 'bottom' wings were improved. The 'top' wing was abandoned and a new line constructed which involved a sharp curve, heavy rock excavations and earth filings to a depth of 60 feet (18 m). The 'bottom' wing was lengthened without any re-location. However, accidents still continued to occur, as was seen on 8 December 1908 when a Sydney bound goods train stalled just beyond Clarence Tunnel. The train was divided into two but the bottom portion accidentally became a runaway and eventually crashed into the rock cutting of Top Points.

In 1908, the top points dead end was extended for longer trains, only to be replaced in 1910.^[3]

In 1908, work began on the Ten-Tunnels Deviation, a double tracked route with a ruling grade of 1:42 as far as the start of the ten tunnels and 1 in 90 through the ten tunnels. The Lithgow Zig Zag was eventually abandoned in 1910, replaced by the Ten-Tunnels Deviation which is still in heavy use as the Main West line to the central-west of NSW and ultimately the trans-Australia line between Sydney and Perth.^[1]

There were plans to replace the section of 1 in 42 from Lithgow to Bottom points with a second horseshoe curve-like longer deviation, or with a spiral, but as this section in the open air could be operated with bank engines, this second stage deviation was never carried out.^[3]

Use following commercial operation

During World War II, the Clarence Tunnel on the Lithgow Zig Zag (along with other tunnels on various lines) 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.^[4]

Preservation

In 1972 a cooperative formed to commerce restoration of rolling stock. In 1975 the line re-opened as a tourist attraction, operating between Clarence and the Bottom Points.

See also

• Lithgow Power Station

Wikimedia Commons has media related to Lithgow Zig Zag.

References

Further reading

• Belbin, Phil; Burke, David (1981). Full steam across the mountains. Sydney: Methuen Australia. p. 144. ISBN 0454002785. 
• Bentley, James; Belbin, Phillip (1988), Black smoke, blue mountains : the great Zig Zag railway, Robert Brown & Associates, ISBN 978-0-949267-58-0 
• Langdon, Mark (2006), Conquering the Blue Mountains, Eveleigh Press, ISBN 978-1-876568-30-6