Great Zig Zag Railway deviation tunnels | NSW Environment & Heritage

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Great Zig Zag Railway deviation tunnels

Item details

Name of item: Great Zig Zag Railway deviation tunnels
Other name/s: Bell to Zig Zag Ten Tunnel Railway Deviation
Type of item: Complex / Group
Group/Collection: Transport - Rail
Category: Railway Tunnel
Location: Lat: -33.4925858296 Long: 150.2184178820
Primary address: Main Western Railway, Lithgow, NSW 2790
Local govt. area: Lithgow
Local Aboriginal Land Council: Bathurst

Boundary:

The tunnels are located between Clarence Station and Zig Zag Bottom Points. The curtilage is the extent of the ten tunnels from the start of tunnel portal 1 to the end of tunnel portal 10, including the rock cliff faces at the portals of each tunnel.
All addresses
Street AddressSuburb/townLGAParishCountyType
Main Western RailwayLithgowLithgow  Primary Address

Statement of significance:

The Ten Tunnel Deviation is of state significance due to its historical associations with the second phase of railway crossing across the Great Dividing Range. It is of a high level of technical significance as a large scale engineering achievement of the early 20th century including excavation of the deepest cutting on the NSW rail system. The project was one of the great railway deviations constructed throughout NSW, and was a success in reducing both journey time and track gradient, and continues to be in use today. The tunnels form part of a larger railway landscape in the Lithgow area and across the Blue Mountains including the Zig Zag railway, Dargan's Creek Deviation, Eskbank Goods Yard and the State Mine Colliery railway.
Date significance updated: 28 Apr 10
Note: The State Heritage Inventory provides information about heritage items listed by local and State government agencies. The State Heritage Inventory is continually being updated by local and State agencies as new information becomes available. Read the OEH copyright and disclaimer.

Description

Designer/Maker: NSW Government Railways
Builder/Maker: NSW Government Railways
Construction years: 1908-1910
Physical description: The deviation comprises ten tunnels of varying length from 77 yards (70 metres) to 902 yards (825 metres). The work also included the excavation of the deepest cutting (200 feet) on the NSW rail system. The tunnels are numbered from the Sydney end of the deviation. The tunnel portals are elliptically shaped with concrete used for floor and up to the start of the arch and brickwork for the arches. The tunnels are of masonry (brick) construction.
Physical condition and/or
Archaeological potential:
Generally good condition.

A 2007 structural report notes the following:
No.1, 3, 4 tunnel water seepage,
No. 6 hairline cracks at Sydney end,
No.9 hairline cracks and water stains,
No.10 water seepage from crown.
Date condition updated:28 Apr 10
Modifications and dates: 1952: Land was acquired for a further deviation between Bottom Points (now Zig Zag platform) and Coal Stage signal box in Lithgow but electrification in 1957 eliminated the need for the deviation.
1978: The conventional use of individual track sleepers in all tunnels was replaced by a continuous concrete bed and was upgraded in 2002/03.
Current use: Railway
Former use: Railway

History

Historical notes: The original 1869 Main Western single line headed north from Mount Victoria along the ridge known as the Darling Causeway. It then turned west and entered the Dargan's Creek valley. After climbing out the head of this valley it reached an escarpment where the Zigzag was constructed to reach the valley floor. The Zig Zag was created by the track switching back on itself twice to reach the bottom of the Great Dividing Range. From here it continued west to Lithgow. This section was opened on 18 October 1869.

The 1869 Zig Zag became a bottleneck to the flow of traffic and as early as 1885, consideration was given to its replacement. In 1897, the first major change was made, known as Dargan's Creek Deviation. This involved traversing the Dargan's Creek Valley on the northern side of the creek instead of the south. The line was still single-track at this point, and this soon became a bottleneck. In order to alleviate this, electric staff crossing loops were added at Edgecombe in 1901 (between Clarence and Top Points) and Dargan's in 1902 (between Bell and Clarence).

In 1906, a new junction and station were constructed at the first Newnes Junction Station. The junction was for the private Newnes Line.

By 1910, it had become evident that a new route was required for the descent to Lithgow. Accordingly a new route, known as the Ten Tunnels Deviation, was built and the Dargan's Creek Deviation was closed. The existing stations were all closed, with Newnes Junction relocated closer to Sydney, and a new Clarence station built where the line goes under the Bells Line of Road. The Newnes Line closed after 25 years of operation in 1932, and only the formation remains.

The Ten Tunnel Deviation started at Newnes Junction and finished at Bottom Points (now Zig Zag platform). As its name suggests, it featured 10 new tunnels, and it bypassed the Zig Zag. The new route broadly followed the previous one as far as Newnes Junction, before turning south and taking a more circuitous route via the tunnels to emerge from the final one near the base of the Zig Zag.

Supplies to the line during construction were provided by a funicular railway that descended 350 feet from the ridge to a location near No.10 tunnel. Up to 1500 day employees worked on the project.

The deviation was a part of the duplication of the Main Western Railway between Penrith and Lithgow. Upon completion, the deviation reduced the route mileage by about five miles and comprised ten tunnels of varying length from 77 yards (70 metres) to 902 yards (825 metres). The work also included the excavation of the deepest cutting (200 feet) on the NSW rail system. Journey times were reduced by between 20 and 30 minutes. Also, the gradient was reduced from 1 in 42 to 1 in 90, thereby allowing a doubling in the loads of trains.

In 1972, a group of enthusiasts formed the Zig Zag Cooperative, and took over the track between the original Clarence station and Bottom Points and today the Zig Zag Railway is a successful tourist operation based at the restored Clarence station. A new Cityrail platform, Zig Zag was constructed on the Main Western line to allow public transport access to the Zig Zag. The previous stations at Newnes Junction and Clarence have closed, with little trace of the latter remaining.

Historic themes

Australian theme (abbrev)New South Wales themeLocal theme
3. Economy-Developing local, regional and national economies Transport-Activities associated with the moving of people and goods from one place to another, and systems for the provision of such movements Engineering the public railway system-

Assessment of significance

SHR Criteria a)
[Historical significance]
The Ten Tunnel Deviation is historically significant as the second phase of the Great Dividing Range railway crossing. The project was one of the great railway deviations and is still in use today. The tunnels form part of a larger railway landscape in the Lithgow area and across the Blue Mountains including the Zig Zag railway, Dargan's Creek Deviation, Eskbank Goods Yard and the State Mine Colliery railway.
SHR Criteria c)
[Aesthetic significance]
The Ten Tunnel Deviation illustrates high level technical achievement for tunnelling, engineering and railway building practices. The work included excavation of the deepest cutting on the NSW rail system. The construction involved up to 1500 employees per day. It resulted in journey times reduced by 30 minutes and the track gradient reduced from 1 in 41 to 1 in 90 which allowed a doubling in the load of trains.
SHR Criteria e)
[Research potential]
The Ten Tunnel Deviation has research significance in providing evidence on the techniques of tunnel construction in the first decade of the 1900s.
SHR Criteria f)
[Rarity]
The Ten Tunnel Deviation is a major engineering achievement in the early 1900s and is rare in this regard.
SHR Criteria g)
[Representativeness]
The Bell to Zig Zag Ten Tunnel Deviation is representative of brick-arch construction used for tunnelling during the early 20th century railway deviations in NSW.
Integrity/Intactness: The Ten Tunnel Deviation is intact and has high integrity.
Assessment criteria: Items are assessed against the PDF State Heritage Register (SHR) Criteria to determine the level of significance. Refer to the Listings below for the level of statutory protection.

Procedures /Exemptions

Section of actDescriptionTitleCommentsAction date
57(2)Exemption to allow workStandard Exemptions SCHEDULE OF STANDARD EXEMPTIONS
HERITAGE ACT 1977
Notice of Order Under Section 57 (2) of the Heritage Act 1977

I, the Minister for Planning, pursuant to subsection 57(2) of the Heritage Act 1977, on the recommendation of the Heritage Council of New South Wales, do by this Order:

1. revoke the Schedule of Exemptions to subsection 57(1) of the Heritage Act made under subsection 57(2) and published in the Government Gazette on 22 February 2008; and

2. grant standard exemptions from subsection 57(1) of the Heritage Act 1977, described in the Schedule attached.

FRANK SARTOR
Minister for Planning
Sydney, 11 July 2008

To view the schedule click on the Standard Exemptions for Works Requiring Heritage Council Approval link below.
Sep 5 2008

PDF Standard exemptions for works requiring Heritage Council approval

Listings

Heritage ListingListing TitleListing NumberGazette DateGazette NumberGazette Page
Heritage Act - State Heritage Register 0103702 Apr 99 271546
Heritage Act - s.170 NSW State agency heritage register     

References, internet links & images

None

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Data source

The information for this entry comes from the following source:
Name: Heritage Office
Database number: 5012082
File number: H98/00287/03; 10/18296


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