|07- Railway Tunnels|
|LITTLE KNOWN TUNNELS
Sydney has a number of little known railway tunnels. The oldest one was built under George Street in 1855 from the Sydney Railway Yard to Darling Harbour. A gap at Broadway let the smoke from the steam trains of those days escape. The tunnel is still in use.
Another old tunnel runs beneath Jubilee Park at Glebe. It forms part of the Metropolitan Goods Line which runs from Darling Harbour to Canterbury. The line was started in 1855 and completed in 1916. As its name implies, the line is used only for goods and, as no passengers travel on it, few people outside the railways know of its existence.
However, the line was known to thousands of American troops who landed at Rozelle Bay during the Second World War. A monument in the Rozelle Marshalling Yards is a reminder of those days.
A number of unused tunnels were built in the 1920s as part of Dr J. J. C. Bradfield's scheme for Sydney's transport. They include tunnels near Wynyard Station which were used for many years by trams. They are now used as a ear park under the Menzies Hotel.
Short tunnels constructed in the 1920s around Town Hall Station were built in case the railway system was extended at some future date when blasting would interfere with normal train operations. The police used one of these tunnels as a pistol practice range for many years. These days they are incorporated in the eastern suburbs railway system. In addition to these, other short tunnels for future extensions were also constructed on either side of St. James. These tunnels, however, are not used in the eastern suburbs network.
The Circular Quay end of the St. James tunnel was used during the Second World War as General MacArthur's headquarters before he moved his operations to Queensland. It is now used by the railways to store trains. The other tunnel extending under Hyde Park remains unused and tree roots have grown down into the roof from the park above.
Another short tunnel built for future railway extensions at North Sydney Station also remains unused. Built as the start of a projected railway extension to Mosman, Manly, Narrabeen and Pittwater, it was completed about the same time as the Sydney Harbour Bridge which opened in 1932. As much as the railway extensions along the North Shore to Pittwater have been discussed, they have never been built.
THE CITY CIRCLE
The most familiar tunnels in Sydney are probably those of the City Circle.
Most of them were built by the cut-and-cover method in the 1920s. The first underground stations, Museum and St. James, were completed and opened to traffic in December 1926. They were electrified from the outset. This system was linked to the North Shore when the Sydney Harbour Bridge was opened in 1932. The City Circle itself was completed with the opening of the Circular Quay loop in 1956, but until that time turnbacks and crossovers had been used.
The City Circle is a complicated system. In one section there is a tunnel running on top of another for half a kilometre. Tunnels cross each other skew-wise at various places. In two Parts there are four tunnels running side by side on the same level.
Later work for the City Railway which was built mainly by the cut and cover technique.
For the most part, the route lay through public parks and under the roadways. The greatest difficulties were encountered where the tunnel had to pass under building foundations on the section between Central and Wynyard. On the eastern side of the city, the bulk of the tunnelling between Goulburn Street and St. James Station was through ironstone clay and shale, with the sandstone mainly below the middle section of the tunnel. This ironstone clay was easily worked but had to be closely timbered. The shale was not particularly hard and lay in blocks cut in irregular directions by narrow clay seams; however, the clay when wet was most treacherous by readily allowing the shale to become dislodged and become a load on the tunnel timbers.
THE EASTERN SUBURBS RAILWAY
The prize for Sydney's most expensive hole in the ground undoubtedly goes to the Eastern Suburbs Railway which opened in 1979 after nearly a century of talking, planning, and delay. It cost a total of $168 million. The tunnels alone cost $50 million and the stations $46 million.
The Eastern Suburbs Railways is a ten-kilometre line basically consisting of seven underground stations linked by tunnels (Redfern, Central, Town Hall, Martin Place, Kings Cross, Edgecliff and Bondi Junction); viaducts across two valleys (at Woolloomooloo and Rushcutters Bay); and one short aboveground section near Woollahra.
City Underground Railway.22 January 1925 (site under Hyde Park- St. James visible on left, nice Victorian building on current Supreme Court site).
There are 1.5 kilometres of open-cut tunnels and seven kilometres of tunnels driven through rock. More than 1.5 million tonnes of sandstone had to be removed.
Australia's most modern commuter line now carries about 60 000 passengers a day or 18 million passengers a year as part of a bus rail transport system. The idea of a railway serving the Eastern Suburbs has inspired generations of planners and politicians and sparked off a score of Royal Commissions and committees of inquiry. Back in the last century, the Sydney railway terminal was called Redfern Station, which was located on what today is the southern side of Devonshire Street (Redfern Station, as we know it, was called Eveleigh). The first proposals for an Eastern Suburbs line were associated with demands that the rail terminal be extended into the cit proper. But in those years, and for many years after, Sydney provided only a quarter of tie population of New South Wales, and the politicians of the day were aware of what this meant to them. A typical view was that of John Sutherland, then Minister for Works, when, in 1868, he was asked to extend the railway from Redfern into the city. Although representing the electorate of Paddington (where the voters favoured a railway), he pointed out that the amount needed to build a railway from Redfern into the city proper would be enough to extend the western line from Bathurst to Orange.
City Underground Railway. Single Line Tunnel before lining, 2 February 1927.
Sutherland's priorities were borne out by events; the railway reached Orange in 1877 but did not get to St. James until 1926.
Strong opposition came also from powerful country interests and the first suburban railways could only get parliamentary approval if they formed part of a line to the country. . .
The first suburban railway -fourteen kilometres from Sydney to Hurstville -was opened in 1884, and two years later it had reached Waterfall. The Strathfield-Hornsby line was opened in 1886 and extended to the Hawkesbury shortly after. Both these lines were proposed to parliament on the basis that they formed part of the Illawarra and Northern lines, but there was no way in which an Eastern Suburbs line could be part of a country service. Another limiting factor was the small population of the Eastern Suburbs
-and numbers are important if a city railway is to be viable.
In 1871, the boroughs of Paddington, Woollahra, Waverley and Randwick contained only 11 000 people. Twenty years later, their population had risen to only 45 000. Waverley, for example, had shown a population increase of 300 per cent to 9000 over the ten Years to 1891, living in 1900 houses. But only one-fifth of its area had been built on.
City Underground Railway. double Tunnel near Circular Quay, 12 June 1931.
The first real attempt to persuade parliament to provide public transport for the Eastern Suburbs came with a draft bill of 1873 to authorise the building of a horse-drawn tramway from Sydney station to the city and to the Eastern Suburbs. This was passed on to a subcommittee for consideration and there it was lost; the fate of many a proposal over the years to come. But given the cost-saving option of building a tramway system to link the city with the Eastern Suburbs, the Government of the day was quick to seize it.
Despite opposition from private transport operators The Tramways Extension Bill was passed early in 1880. The first line from Liverpool Street to Randwick Racecourse was opened in 1880, with an extension to Randwick in March 1881 -the same month as the Darlinghurst-Ocean Street line came into service. The tramway network gradually spread across the suburbs, reaching Bondi Beach in 1894, Rose Bay in 1898 and Watsons Bay in 1909.
Despite the success of the trams, a rail link continued to be urged on a series of reluctant governments. In 1890 a Royal Commission proposed the building of a city terminal and the extension of four tracks into the city terminating at Circular Quay, with provision for an extension to the Eastern Suburbs. But no action was taken, nor was there any action after another Royal Commission made similar suggestions in 1896.
Central Station was built in 1906 but the agitation for a City and Eastern Suburbs railway continued, and plans continued to be drawn up and pigeonholed.
Finally, in 1915, parliament approved a proposal for a City and Eastern Suburbs railway drawn up by Dr J. J. C. Bradfield, the Chief Engineer of the Metropolitan Railway Construction. This entailed the building of the present City Circle loop, with provision for a rail link off this to the Eastern Suburbs via a tunnel beneath the Domain and a viaduct over Woolloomooloo to Kings Cross. .'
There were to be stations at Glenmore Road in Paddington at a site near Elizabeth Street, Woollahra, Bondi Junction, Waverley, Little Coogee (near Frenchman's Road, Randwick), Coogee (near High Street and Belmore Road), Daceyville, Rosebery and Waterloo linking with the Illawarra line near Erskineville Station.
The visionary Dr Bradfield (planner of both the Sydney Underground Railway and the
Sydney Harbour Bridge) foresaw an extension from Bondi Junction to Watsons Bay and
an inner loop between Central Station and Daceyville with stations at Moore Park
(serving Sydney Cricket Ground, Sports Ground and Showground), and at Randwick Racecourse.
During the 1920s work continued. on the city railway 'to complete the Town Hall-
Wynyard link in time for the opening of the Harbour Bridge but still the eastern extensions languished, despite regular demands for the work to begin. After paying for the city railway, the Governments of the day could not find the funds to extend the work.
In 1947, an Act was passed authorising completion of the City Circle and railway extensions into the suburbs (including the eastern link) which provided for a station at Martin Place with the line going on a viaduct over Woolloomooloo to Kings Cross and eventually to Bondi Beach. Another line was to go out from St. James via Taylor Square and the Cricket Ground to terminate at Kingsford, with a further extension from Taylor Square via Paddington, Woollahra, Bondi Junction, Waverley, Bronte, and Clovelly to Coogee.
Excavations outside Central Station.
Dr Bradfield, designer of the City Railway (centre), with o group outside Central Station in 1926.
Work proceeded slowly until 1952 when a recession caused the Government to order a halt. By this time, tunnels had been driven from the Domain to a point beneath Rowe Street; the Chalmers Street excavation had been completed; tunnels driven a short distance from a shaft in Prince Alfred Park; and some of the work at Erskineville and Redfern had been carried out.
In 1962, the Government commissioned a report from overseas experts, De Leuw Cather and Company which recommended that the line be completed basically on the earlier route to Bondi Junction thence proceeding to Kingsford. Nothing was done on this report until 1967 when an Act covering the proposal was passed and work actually began.
In 1976, the Government abandoned the section from Bondi Junction to Kingsford as recommended by the Urban Transport Advisory Committee and commissioned a report by an Eastern Suburbs Railway Board of Review. In November 1976 the Government accepted that Board's recommendation to proceed with the project with certain modifications to reduce costs. The cost-saving decisions announced at this time included the elimination of the proposed station at Woollahra and reduction of station concourse areas at Martin Place and Bondi Junction.
Not all of the work of the planners of the past has been lost in the development of the new railway. The stations are close to the locations envisaged by the engineers and designers long ago and the platforms at Tow Hall Station which handle the Eastern Suburbs traffic were partly built by Dr Bradfield laid a century ago as part of his city and suburban system to cater for a new line he envisaged to serve the western suburbs.
The Eastern Suburbs Railway was one of the largest engineering projects ever undertaken by the New South Wales Government.
The route was determined to some extent. by the undulating terrain of the eastern suburbs of Sydney and the need to avoid building foundations and poor ground material, where possible.
Erskineville is where the Eastern Suburbs Railway connects with the existing metropolitan rail network. The new line descends rapidly down a ramp (with a grade of 1/32) into twin-box tunnels extending 1.3 kilometres beneath Alexandria Goods Yard to Redfern Station. These tunnels were constructed by the cut-and-cover method because of the difficult ground conditions in this area of water-laden alluvial soil. Extensive sheet piling was required as this method was used at depths of up to sixteen metres. This work proved to be very difficult and expensive. Redfern Station platform, located fifteen metres below ground level, marks the point when it became practical to use conventional means of drilling and blasting in the tunnelling works.
This method was used in the tunnels from Redfern to the Domain portal at Woolloomooloo and beneath Kings Cross. Generally, conventional tunnelling involved full-face firing of a 2.8 round (120 holes and up to two rounds per shift). Monitoring of ground vibration was necessary in most areas to protect buildings. The roof of the tunnels was usually supported with four metre rock bolts. The tunnels were finished with a concrete lining varying in thickness from 200 to 600 millimetres.
The section between Edgecliff and Bondi Junction was formed by the use of a 179-tonne tunnel-boring machine known as the "Mole". In principle, the machine consisted of a rotary cutting head pressed on to the tunnel face by a large hydraulic ram. The 4.5-metre diameter cutting head was driven by large hydraulic motors and gouged away the face at a rate of two metres per hour.
Equipment involved in these works included rock bolting systems for roof support, high-speed drifters mounted on hydraulic booms or air legs, millisecond delay detonators with mains voltage firing, truck mounted hydraulic drilling platforms, heavy earthmoving equipment such as loaders and rock buggies, concrete pumps, concrete immersion and form vibrators, steel formwork and concrete placing systems which allowed lining of the tunnels at rate of thirty metres per day.
The tunnelling work on the Eastern Suburbs Railway was speeded up by a tunnel-boring machine appropriately named "The Mole': shown here at the Woollahra Portal.
Before: An early construction photo showing the excavation beneath Chalmers Street for the new Eastern Suburbs Railway platforms.
After: Restored Chalmers Street with its attractively landscaped pedestrian boulevard above the Eastern Suburbs Railway.
Tunnels are usually wet areas and, consequently, must be drained. In the Eastern Suburbs Railway network, weep holes were left in the walls and the water drained to pump chambers located at the lower points of the system. These chambers up to fifteen metres below sea level have pumps which are automatically activated as the water level rises. The water is pumped to the surface and discharged into stormwater drains. During construction of the line it was necessary to support building footings under the city and at Kings Cross. One column footing of the State Theatre building located directly above the crown of the tunnel was underpinned. This necessitated an inclined drive up to the footing and the excavation of a chamber around it. Steel beams were installed on each side of the footing on concrete pads clear of the tunnel and the footing was gradually picked up on needle beams supported by flat jacks.
A more complex effort was necessary at Kings Cross where the track above the station area was prestressed in order to minimise settlement when the arches were excavated. The first move was to install heavy steel beams and columns of flat jacks in the column drives.. The beams were surrounded in concrete and grout forced between the concrete and the rock. The flat jacks were pressurised and had the effect of raising the roof level about six millimetres. The centre arch was then excavated and lined and then the outer arches excavated and lined. The maximum final settlement recorded at street level was about 9.5 millimetres and no damage was caused.
Further construction problems were encountered where the tunnels crossed underneath the existing City Circle tunnels just east of Martin Place. Extensive steel supports were required to prevent subsidence of the overlying rock which is heavily stressed by City Circle train loads less than three metres above the new tunnels.
The construction of the Redfern and Central Stations, located on the eastern side of the existing railway was commenced in the 1947-52 period. At that time, the stations were excavated by open cut methods and the steel frame structures of the stations were erected. When work ceased in 1952, the steel was left exposed; by 1967 these steel structures had corroded badly and major remedial work was required.
Whereas these stations were excavated from the surface down, the lower levels of Martin Place, Kings Cross and Bondi Junction Stations were excavated and lined by tunnelling methods. However, the concourses were constructed in excavations opened from the surface and are connected to the platform level by escalator shafts. Since it was not feasible in the Martin Place and Kings Cross areas to excavate using explosives, the concourse excavations were completed using large dozers with ripping attachments and hand-held pneumatic tools.
As the station structural works were completed, the finishing trades moved in. A high standard was demanded in this work through use of mosaic tiles and various coatings on the walls, suspended moulded panels for ceilings and floor surfaces of either terrazzo, exposed aggregate or rubber.
|This section is based on the excellent book by Brian and Barbara Kennedy. (Subterranean Sydney (The Real Underworld of Sydney Town), Reed, Sydney, 1982. ISBN 0 589 50312 X). Copyright Brian and Barbara Kennedy and Reed Publishing.|