Sydney Harbour Tunnel - Greenwich to Balmain | NSW Environment & Heritage

Culture and heritage


Sydney Harbour Tunnel - Greenwich to Balmain

Item details

Name of item: Sydney Harbour Tunnel - Greenwich to Balmain
Other name/s: Cnr Numa Street
Type of item: Archaeological-Terrestrial
Group/Collection: Utilities - Electricity
Category: Other - Utilities - Electricity
Primary address: 146A& 146B Louisa Road, Birchgrove, NSW 2041
County: Cumberland
Local govt. area: Leichhardt
All addresses
Street AddressSuburb/townLGAParishCountyType
146A& 146B Louisa RoadBirchgroveLeichhardt CumberlandPrimary Address

Statement of significance:

The site of Nos. 146A and 146B Louisa Road is of historic significance as the entry point and Balmain end of the first tunnel built under Sydney Harbour between Long Nose Point, Birchgrove, and Manns Point, Greenwich. Constructed between 1913 and 1926 to carry submarine electricity cables for the electric tramway and (later) rail system on the north side of the Harbour, it significantly continued to operate for over 40 years. Whilst no longer in use (ceased use in 1969) and no evidence of the entry remains above ground at this end, the shaft and tunnel structure (and early cabling) remain below ground as evidence of significant infrastructure designed and constructed by State Rail.

Note: This inventory sheet is not intended to be a definitive study of the heritage item, therefore information may not be accurate and complete. The information should be regarded as a general guide. Further research is always recommended as part of the preparation of development proposals for heritage items.

Council's Library Service has identified a map/plan: Snails Bay or Minature Bay of Naples : Surveyor's notes, relating to this item which may be viewed online through the council website at Select Library & Local History to get to the Library online catalogue and keyword search the street name for results.
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.


Builder/Maker: Department of Railways
Construction years: 1913-1926
Physical description: Corner site occupied by a pair of two storey rendered brick modern semi detached buildings with curved and flat roof forms and garages constructed to the Louisa Road frontage. The buildings are constructed to the Numa Street frontage with high rendred walls located along the street corner and rear of the site and shared boundary with No. 2 Numa Street. Some stone kerbing runs along the south western side of the Numa Street alignment. Stone walls and features are also located further along Numa Street.
Physical condition and/or
Archaeological potential:
There is no visiable evidence of the former entry to the tunnel which ran diagonally across the site previously known as No. 146 Louisa Road.
Date condition updated:14 Feb 11
Modifications and dates: 1989: Reinforced slab over mine shaft (89/709).
1993: Two, two storey semi-detached brick dwellings (92/696).
Current use: None
Former use: Tunnel housing cabling


Historical notes: The area around Snails Bay to Long Nose Point and bounded by Cove and Grove Streets, approximately 30 acres, was originally granted to George Whitfield of the NSW Corps in 1796. He named his grant “Whitfields Farm”. The land changed ownership a couple of times before it was acquired by Lieutenant John Birch in 1810. Birch built Birch Grove House, the first house on the Balmain peninsula (at 67 Louisa Road, demolished 1967). Birch left the colony in 1814 and sold the house to Rowland Walpole Loane. Loane tried to subdivide the land into four lots in 1833, however, this was unsuccessful. The area was difficult to access (the ferry system was not started until 1836) and the odours from the mudflats around the bay may have also contributed to the lack of interest. Loane sold the house in 1838. A series of owners and tenants followed, but the house remained the only building in the area for another two decades.
In 1854 the Estate was purchased by Didier Joubert, who with his brother was responsible for the development in Hunters Hill and also established the Parramatta Ferry Service. He commissioned Surveyor Brownrigg to subdivide the land which provided the backbone of the area today. The street names were derived from family members including Joubert’s wife (Louisa), children (Numa and Rose) and nephew (Ferdinand) with boundaries defined by (Iron) Cove Road and (Birch) Grove Road. Birch Grove House remained undisturbed. Louisa Road followed the ridge and prominent bend still stems from this time. The 1860 sale was premature and within 6 years only 7 allotments had been sold. Joubert sold Birch Grove House in 1860 to Jacob Levi Montefiore. His Bank sold all the remaining land in December 1862.
A new consortium comprising of Archibold McLean, Thomas McGregor, both merchants and auctioneer Lancelot Edward Threlkeld commissioned Surveyor Reuss Junior to re-examine the Brownrigg plan and make some amendments around the head of the bay and along the steepest part of Louisa Road to create more usable allotments. The estate was again put up for sale in 1878. Street frontages varied between 50 to 70 feet with a depth of about 150 feet. The terrain and generous proportions of the blocks made the precinct ideal for the construction of substantial free-standing dwellings, but by 1882 only 53 residences stood on the estate. Stonemasons and quarrymen were among the first purchasers. Other early occupants were professionals who travelled to town by ferry and small speculators or builders who quarried the land or buildings elsewhere. The boom period, however, later saw more lots taken up and villas were constructed in stone or rendered brick with later grand residences constructed in the Federation period.
The site, part of Lot 24 Section 5 of the subdivision was purchased by George Hitchcock, a quarryman from Booth Street in 1861. Hitchcock constructed a weatherboard cottage, “Tabak” on the corner of the site and Louisa Road frontage in 1878. The site was subdivided in 1884 and western portion of the site with water frontage sold at this time.
A Sydney Water plan dating from the 1880s (Balmain Sheet No. 1), shows the divided lot occupied by two dwellings. The dwelling in the eastern portion is shown close to the Louisa Road frontage, near the shared boundary with No. 144 Louisa Road. Steps extend from the street frontage up to the front verandah which runs across the front of the building. A verandah is also shown across the rear of the building. Two detached structures are also clear behind the house. Hitchcock continued to occupy “Tabak” until 1901 from aroundwhic time it is assumed that the State Railways purchased the site. The house was demolished in 1912 and construction of a Sydney Harbour tunnel commenced from this time.
The tunnel was built between Long Nose Point, Balmain, and Manns Point, Greenwich, from 1913 to 1926 to carry submarine electricity cables for the electric tramway system on the north side of the Harbour as submarine cables laid across the bed of the harbour had suffered damage from ships and their anchors.
The first tram route on the northern side of the harbour was established in September 1893 and stretched between Falcon Street, North Sydney and Spit Road. It was extended to Mosman Bay in 1896. Steam trams already ran south of the harbour and by 1904 the conversion of this network to electricity was well underway. The railway and tramway power stations at White Bay and Ultimo were increasing their capacity and a new electric substation was constructed at North Sydnety to serve the expanding tramway system. Cables were laid across the bed of the Harbour to feed the power from White Bay to North Sydney.
The obvious location was the shortest distiance which was between Long Nose Point and Manns Point at Greenwich. By 1912 the expansion of the tramway network and need for more power and communication meant that more cables were required. To protect these cables it was decided to construct an underground tunnel to house them. Work commenced in October 1913 at the Long Nose Point end, at the corner of Louisa Road and Numa Street. The steam railway service from Hornsby to St Leonards was established in 1890 and extended to Milsons Point in 1893. This service was converted to electricity in 1927, the year after the competion of the tunnel.
Despite careful lining leaks kept occurring. The tunnel was flooded about 1930, whether intentionally to avoid continual pumping or as the result of a sudden inrush of water, is not clear. During the construction of the Sydney Harbour Bridge the railway communication cables were re-routed via the Bridge. The electricity cables in the flooded tunnel were completed sheathed and remained in use until 1969, but are no longer used due to ample supplies of electricity now available on the north side of the harbour from electricity substations. In 1952 the Electricity Commission was formed to take over the generation of all electric power in NSW. The power stations in White Bay and Ultimo were taken over, but the tunnel and its cables remained the property of the State Rail Authority.
When it was built, the tunnel was one of Australia's major engineering feats. A description by a reporter from The Sun newspaper in 1924 noted the following:
“There is not much outward evidence of this great work. At the Long Nose Point there is the usual pit-head working and-the mouth of the tunnel. At the Greenwich side there are two openings. A shaft nearer the water, which descends directly down into the bowels of the earth, and further up the hill, another opening where the slope downward commences.
The atmosphere was cool and pleasant, electric light bulbs twinkled like golden glow worms, and here and there the water trickled slowly in from the roof and sides; in one or two places outlet pipes discharged a flow of percolated water into the bed of the tunnel. A little light railway ran right through, at odd spots few men worked putting the finishing touches to a job which they talk of with pride. Running the length on one side were cement racks to hold the high tension wires which will supply electric power for trams and trains on the north side of the harbour. At one end was a pool some six feet in depth, where the soakage collects, and is pumped to the surface.
The tunnel is perfectly straight, except at Greenwich Point, where it takes a bend to allow an outlet at a suitable spot. From outlet to outlet it measures 1,760 feet. At each shaft it descends steeply into the ground at a grade of 2 in 1, except in a section at the Greenwich end; where a steep cut had to he made to avoid trouble. Here the grade is 1 in 1.3.
On the level of the tunnel it is possible to walk upright with ease. In fact, two or three men could walk abreast, and there is ample room for any working party to repair the cables.”
The construction job itself was a series of "Homeric battles": The work was started from three points; Long Nose Point, Greenwich, and a shaft at the extreme end of Mann Point, which is a continuation, more or less, of Greenwich. Initially progress was rapid, however some probelmes were encountered. First of all, the residents of Long Nose Point, in letters and protests very much to the point, caused the abandonment of the Long Nose end after a considerable distance had been excavated. Work, therefore, progressed slowly on from the north side until about May 1915, when a large fissure in the rock was found in the approximate middle of the Parramatta River. The only solution was to seal up the tunnel and patch the fissure. A bulkhead was built into the tunnel to stop the progress of the sand, water and silt and a staging was built in the middle of the river and drills were bored through the riverbed. Pipes were inserted through the holes and a cement mixture was gradually pumped into the tunnel in the vicinity of the fissure.
The cement pumping operation was repeated through three other pipes in line with the original ones and the tunnel was sealed twice and allowed to set. The door was then re-opened and the silt and sand removed. A second sealing showed signs of weakness so it was decided to abandon the top tunnel and go deeper into the rock. A permanent bulkhead was built into the rock and the tunnel was sealed up with about 15 feet of concrete that remains today.
A second tunnel was commenced 50 feet below the first one. The down grade was increased to 1 in 1.3. The work was carried out with explosives and some progress was made, however; on arrival at the point immediately below the original break-in, another crevice was struck and water rushed in. On this occasion, the engineer in chief, RL Rankin and the resident engineer WRH Melville, decided to go with the foreman and have a look at the fissure that had flooded the tunnel. Placing candles on pieces of wood, they swam about 40 feet into the centre of the tunnel. It was a risky job. The surface of the water was less than a yard from the top of the tunnel and if the inflow had suddenly increased, they would have been caught. The break-in was later sealed by placing 6-inch pipes, about 15 yards long, into the crevice, and the whole of the tunnel in the immediate vicinity was packed with bags of clay and tightly rammed. In front of this was placed a steel bulkhead with a steel door and through the bulkhead three-inch pipes were laid right into the crevice, to allow the water to get out. Through the 6-inch pipes cement was pumped until finally it was not possible to shoot any more into the crevice under very heavy pressure. This was allowed to set for about three months. When the bulkhead door was opened it was found that the inflow had practically stopped. The bags of clay were completely cemented together and a detour was cut at this point to about 6 feet, to get round the crevice, and when the men had passed it they worked back to the original line of excavation.
The section of the tunnel that had been sealed up was cut through, the detour filled in, and the original straight line of excavation restored. After going about 50 feet past the crevice, they struck another small fissure, which was apparently a section of the original one, and water suddenly flowed in at the rate of about 2400 gallons an hour. This was not sufficient to stop the progress of the work, but pumps were installed to cope with the inflow.
Soon after the men began to work on the up-grade, and here great care had to be exercised to prevent the material falling back on them. The material was cut out by channelling machines, which allowed it to be removed without difficulty. Eventually the work broke through and the opening at the Long Nose Point side was in sight. Their calculations had been made with remarkable accuracy. The centre line, when the tunnel was connected, was only 1/8th of an inch out, while the levels were absolutely correct.
The entry point on the site was concealed within a boat building shed and business which operated on the site until this time. The shed was demolished in the late 1980s. In 1989 a Development Application was submitted to Council in relation to the the construction of a reinforced slab over a mine shaft. The slab extended diagonally fron the south eastern corner of the site and Louisa Road frontage to Numa Street. A heavy duty cover and ladder was provided over the tunnel entry in the south eastern section of the site. In 1992 a Development Application was submitted to Council for the construction of two, two storey semi-detached dwellings on the site. The application was approved and dwellings were subsequently constructed. The houses attached garages and walled courtyards cover the entire site and were constructed over the tunnel.

Historic themes

Australian theme (abbrev)New South Wales themeLocal theme
3. Economy-Developing local, regional and national economies Communication-Activities relating to the creation and conveyance of information (none)-
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 (none)-
4. Settlement-Building settlements, towns and cities Towns, suburbs and villages-Activities associated with creating, planning and managing urban functions, landscapes and lifestyles in towns, suburbs and villages (none)-
4. Settlement-Building settlements, towns and cities Utilities-Activities associated with the provision of services, especially on a communal basis (none)-
5. Working-Working Labour-Activities associated with work practises and organised and unorganised labour (none)-

Assessment of significance

SHR Criteria a)
[Historical significance]
The site is significant as the entry point of the Balmain end of the first Sydney Harbour Tunnel built between Long Nose Point, Birchgrove, and Manns Point, Greenwich, from 1913 to 1924 to carry submarine electricity cables for the electric tramway system on the north side of the Harbour.
SHR Criteria b)
[Associative significance]
The site is associated with the Railway Department who constructed, used and maintained the tunnel.
SHR Criteria c)
[Aesthetic significance]
No evidence of the entry remains above ground and tunnel is now flooded, however, the shaft and tunnel structure (and early cabling) remain.
SHR Criteria e)
[Research potential]
Whilst no longer in use, the tunnel was the first Sydney Harbour tunnel constructed in the early decades of the 20th century and continued to provide electricity for tram and railway services for over 40 years.
Integrity/Intactness: Unknown
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:

It is recommended that: - any future major proposed works and excavations to Nos. 146A and 146B protect any potential archaeological resources and evidence of the tunnel.


Heritage ListingListing TitleListing NumberGazette DateGazette NumberGazette Page
Local Environmental Plan  23 Dec 13   

Study details

TitleYearNumberAuthorInspected byGuidelines used
Leichhardt Municipality Heritage Study1990 McDonald McPhee Pty Ltd (Craig Burton, Wendy Thorp)  Yes

References, internet links & images

TypeAuthorYearTitleInternet Links
WrittenMax Solling and Peter Reynolds1997Leichhardt: On the Margins of the City

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: Local Government
Database number: 1940571

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