Otford Railway Tunnel (Former) | NSW Environment & Heritage

Culture and heritage


Otford Railway Tunnel (Former)

Item details

Name of item: Otford Railway Tunnel (Former)
Type of item: Built
Group/Collection: Transport - Rail
Category: Railway Tunnel
Primary address: Chellow Dene Avenue, Stanwell Park, NSW 2508
Local govt. area: Wollongong City


5 metres outside the tunnel portals, the tunnel structure, and the vent shafts.
All addresses
Street AddressSuburb/townLGAParishCountyType
Chellow Dene AvenueStanwell ParkWollongong City  Primary Address
Otford RoadOtfordWollongong City  Alternate Address


Organisation NameOwner CategoryDate Ownership Updated
RailCorpState Government 
RailCorpState Government 
RailCorpState Government 

Statement of significance:

The Otford Railway Tunnel - including the tunnel structure, sandstone dish drain and ventilation stack - is of State heritage significance. It was the longest and steepest single line tunnel to be built at the time (1824m long with a 1 in 40 gradient) as part of a major engineering work built in 1888 to connect the Illawarra line to Sydney. It is part of a notoriously steep section of the Illawarra line south of Waterfall used in the late 19th century by steam trains and bypassed by the Helensburgh deviation in 1919. The Otford tunnel is of technical significance as an important engineering work in the early construction of the Illawarra line and was also used during the second world war as part of an explosives program. Its elaborate system of venting is an important historical remnant of the problems encountered in working this tunnel.
Date significance updated: 09 Jul 09
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.


Designer/Maker: NSW Government Railway
Builder/Maker: Tunnel - W. Rowe & W. Smith, Vent shaft-Mr. Mc Donald
Construction years: 1888-
Physical description: PRECINCT ELEMENTS
Tunnel including entrance and approaches (1888)
Vent shaft to tunnel (1891)

The tunnel is accessed from its southern portal at Stanwell Park, at the end of Chellow Dene Avenue (Lawrence Hargrave Memorial Park). The northern portal is approximately 440m south-west of Otford Railway Station, and is accessed from Otford Road (close to intersection with Station Road).

(South portal only inspected). This is a disused concrete and brick arched 1824m long single track tunnel. The tunnel originally had a sandstone dish drain running through it, covered by large sandstone slabs, however much of the sandstone has been removed. The track bed and drain are estimated to be approximately 1.3 m below the current surface. The 1891 brick vent shaft is located halfway along the length of the tunnel.

Southern portal: There is a sandstone keystone to the centre of the arch. Steel security gates are located at the southern portal at Stanwell Park.

Northern portal: the northern portal is approximately 440m south of Otford Railway Station, and is accessed from Station Road, Otford.

Remains of buildings, foundations etc for ventilating plant, near the northern portal of the tunnel.
Physical condition and/or
Archaeological potential:
Moderate: The southern portal needs new steel security gates to prevent wildlife and public entry. (2009). The condition of the track bed, ballast and central sandstone draining varies along the length of the tunnel (2000).
Date condition updated:09 Jul 09
Modifications and dates: 1891: Vent shaft constructed
1907: Speed indicator
1908: Fan
1919: Wind indicator
Current use: Disused
Former use: Pedestrian Path 1921, Mushroom Farm 1961, Tours to 2000, Sydney Water Saver


Historical notes: "Otford was formerly known as Bulgo. Bulgo appears to have been first marked on Robert Dixon's 'Map of the Colony of New South Wales' in 1842 and the name continued in use for some time. Construction of the Illawarra line, north of Clifton, brought the appearance of a village here in early 1885. Trains on the Illawarra line stopped here to take in water and a small railway and sawmill centre developed at the mouth of the Otford tunnel. The name of the village changed to Otford in May 1885. Otford was probably named after the historic village of Otford in West Kent, England, the name meaning 'otta's ford'." (Otford locality history on www.wollongong.nsw.gov.au/library).

The Otford Railway Tunnel was constructed in 1888 by the firm Rowe and Smith, who built 7 of the 8 original tunnels on the Illawarra line from Waterfall to Clifton. The Otford Railway Tunnel, the seventh after Waterfall, was the final major engineering project which permitted the linking up of the northern part of the Illawarra Line to the isolated southern part in 1888. The Otford Railway Tunnel opened on 3 October 1888. The single line connection was made at (old) Stanwell Park Station (now by- passed by the 1915 Stanwell Park Deviation).

The tunnel was built of brick arched form and when built was the largest and steepest (5,985 feet long - 1824m - and 1 in 40 gradient) on the system.

Of the 8 original tunnels in the Waterfall to Clifton section of the Illawarra line, the Otford tunnel and the Metropolitan tunnel were notorious for hot and suffocating conditions experienced by the crew of steam trains climbing to Waterfall from Thirroul. There were cases of enginemen burnt by the heat. Due to these conditions, the single line section became an operational bottleneck. To negotiate the steep terrain, train loads were reduced by up to 50% of capacity. This was partly solved in 1891 by building of a brick circular ventilation shaft 7 feet in diameter down 200 feet to the tunnel. Due to the ongoing ventilation problems in the tunnel, the use of electric locomotives in the tunnel was considered, however by 1904 plans for a new set of tunnels (known as the "Helensburgh Deviation") were well advanced, so make-do measures were introduced to minimise the smoke problem. With the use of longer or double headed trains, smoke problems necessitated installation in 1908 of a forced air fan at the northern end of the tunnel.

In 1915 the Helensburgh deviation was under construction to create a set of new tunnels deviating around the Stanwell Park amphitheatre: the duplicated line was able to fully bypass the Otford tunnel and it was closed on 10 October 1920.

The Otford Tunnel was subsequently used as a pedestrian access from Otford to Stanwell Park.

In 1942/43, as part of a war-time explosives programme, the Army detonated a section of roof approximately 1630m to 1643m into the tunnel.

In 1959 the tunnel was used by Eden Industries to farm mushrooms. The debris created by the 1942/43 explosion was cleared away, and a 13m box-like reinforced concrete section was built to replace the brick walls demolished in the explosion and support the tunnel structure.

The tunnel was closed for public access in 2000. RailCorp has placed security gates at the southern portal at Stanwell Park to deter vandalism.

Historic themes

Australian theme (abbrev)New South Wales themeLocal theme
3. Economy-Developing local, regional and national economies Technology-Activities and processes associated with the knowledge or use of mechanical arts and applied sciences Locomotive Design and technological development-
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 Building the railway network-
8. Culture-Developing cultural institutions and ways of life Creative endeavour-Activities associated with the production and performance of literary, artistic, architectural and other imaginative, interpretive or inventive works; and/or associated with the production and expression of cultural phenomena; and/or environments that have inspired such creative activities. (none)-

Assessment of significance

SHR Criteria a)
[Historical significance]
The Otford tunnel is of historical significance as a major engineering work built 1888 to connect the Illawarra line to Sydney. It is part of a notoriously steep section of the Illawarra line south of Waterfall used in the late 19th century by steam trains, and bypassed by the Helensburgh deviation in 1919.
SHR Criteria c)
[Aesthetic significance]
The Otford tunnel is of technical significance as an important engineering work in the early construction of the Illawarra line. It was the longest and steepest single line tunnel to be built at the time (5,985 ' -1824m) long, with a 1 in 40 gradient). Its elaborate system of venting is an important historical remnant of the problems encountered in working this tunnel.
SHR Criteria e)
[Research potential]
The tunnel has research potential for its ability to reveal late 19th century tunnel construction techniques, including early industrial use of concrete.
SHR Criteria f)
The tunnel is rare as a relatively intact 1888 tunnel built for the operation of steam trains on the Illawarra line through the difficult Waterfall to Clifton terrain.
SHR Criteria g)
Representative of late 19th century tunnels built by Rowe & Smith for the Illawarra line from Waterfall to Clifton.
Integrity/Intactness: Relatively intact, damaged and reshored section from 1942/43 explosion, some loss of sandstone from dish drain.
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.

Recommended management:

1. Conservation principles: Conserve cultural heritage significance and minimise impacts on heritage values and fabric in accordance with the ‘Australia ICOMOS Charter for Places of Cultural Significance’. 2. Specialist advice: Seek advice from a qualified heritage specialist during all phases of a proposed project from feasibility, concept and option planning stage; detailed design; heritage approval and assessment; through to construction and finalisation. 3. Documentation: Prepare a Statement of Heritage Impact (SOHI) to assess, minimise and prevent heritage impacts as part of the assessment and approval phase of a project. Prepare a Conservation Management Plan (CMP) prior to proposing major works (such as new additions, change of use or proposed demolition) at all places of State significance and all complex sites of Local significance. 4. Maintenance and repair: Undertake annual inspections and proactive routine maintenance works to conserve heritage fabric in accordance with the ‘Minimum Standards of Maintenance & Repair’. 5. Movable heritage: Retain in situ and care for historic contents, fixtures, fittings, equipment and objects which contribute to cultural heritage significance. Return or reinstate missing features or relocated items where opportunities arise. 6. Aboriginal, archaeology and natural heritage: Consider all aspects of potential heritage significance as part of assessing and minimising potential impacts, including Aboriginal, archaeology and natural heritage. 7. Unidentified heritage items: Heritage inventory sheets do not describe or capture all contributory heritage items within an identified curtilage (such as minor buildings, structures, archaeology, landscape elements, movable heritage and significant interiors and finishes). Ensure heritage advice is sought on all proposed changes within a curtilage to conserve heritage significance. 8. Recording and register update: Record changes at heritage places through adequate project records and archival photography. Notify all changes to the Section 170 Heritage & Conservation Register administrator upon project completion.


Heritage ListingListing TitleListing NumberGazette DateGazette NumberGazette Page
Heritage Act - s.170 NSW State agency heritage registerSRA s.170 Register    

Study details

TitleYearNumberAuthorInspected byGuidelines used
State Rail Authority Heritage Register Study1999SRA152State Rail Authority  No
Heritage and Conservation Register State Rail Authority of NSW1993273Paul Davies for SRA  No
S170 Heritage & Conservation Register Update2009 Paul Davies Pty Ltd  Yes

References, internet links & images

TypeAuthorYearTitleInternet Links
WrittenDavid Sheedy2009Historical Research for RailCorp S170 Register Update
WrittenJ. Oakes2003Sydney’s Forgotten Illawarra Railways

Note: internet links may be to web pages, documents or images.

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Data source

The information for this entry comes from the following source:
Name: State Government
Database number: 4801152

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