|05- Telephone Tunnels|
The next time you walk up Pitt Street and see an elaborate iron manhole cover, spare a thought for the Telecom linemen working just a few metres below, in a labyrinth of tunnels which connect the main Sydney telephone exchanges.
Telecom's maze of tunnels is one of the largest in subterranean Sydney. The whole network stretches for more than twenty kilometres and is so extensive that signs have been marked on the walls at the various cross streets so that the linemen can tell where they are.
Starting at the Dalley Street Exchange near Circular Quay, you go down to the tunnel where all the telephone cables enter the exchange. You pass under a notice telling you a little about the old Tank Stream which is now to your right and slightly above you. The Tank Stream is now a bricked-in drain and is no problem. Normal rain from the average Sydney downpour is much more of a hazard and flash floods from a storm frequently flood the tunnels to the top in the lower areas.
The first part of the tunnel leads down well below the level of the old Tank Stream. You walk along under Dalley Street and then turn right and climb up just below the surface under Pitt Street. Through the holes in the grille work of the old iron manhole covers you can, clearly see and hear the ~people passing by a few metres above your head quite oblivious of your presence.
The Dalley Street tunnel, built about 1950, is a clean concrete affair, well lit and with plenty of room to walk and work in. But walking up under Pitt Street a little way you soon reach the old brick tunnels which were constructed in the 1890s. These, too, are lit with electric bulbs at intervals but head room is restricted and you are forced to walk hunched over, trying not to knock your safety helmet on the cast iron brackets that hold the brick arch in place. From here you can stroll by tunnel all the way to Newtown or to Oxford Street if you so desire -but in such a back-breaking, doubled-over position, it is not the most pleasant prospect. Fortunately for the men who work in the tunnels, the network is divided into sections so that nobody has to walk that far. Even so, working conditions are cramped. Each day, technicians have to walk along the tunnels to inspect the telephone cables and the old-fashioned pneumatic tube that is still used to deliver telegrams between the GPO and the Royal Exchange Post Office. (This Post Office is so named because of its proximity to the Royal Exchange which used to occupy a building in Bridge Street and still has premises in Gresham Street today. It was the nineteenth century Royal Exchange -a collection of business and professional people -who brought the first permanent telephone connections to Sydney.)
The first Sydney telephone system was connected to the Royal Exchange in 1880.
The pneumatic tube system is also used still between the Chief Telegraph Office in the GPO and Sydney South, Clarence Street, and Haymarket post offices. The Overseas Telecommunications Commission in Martin Place is also served by the system.
Poison baits are laid to keep down the rats which chew through the cables. Gas leaks are a constant danger. The Telecom technicians use cockroaches the way the miners used canaries. If the cockroaches are alive, the air is okay. If they are dead, it means trouble.
The greatest danger is flash flooding which can send a worker fleeing for the nearest manhole while his tool bag is swept away over a waterfall which can be ten metres high in places where the tunnel dips to go below the level of the Tank Stream.
However the tunnels are much more pleasant places to work in today than they were even thirty years ago when hurricane lamps provided the only light and sewerage from certain buildings shared the drainage system of the tunnels. The sewerage has now been diverted to the sewer and the tunnels are now lit by electric light.
The cables themselves have changed, too, from the heavy lead-sheathed affairs that once carried messages under the city. Now modern plastic covered cables carry up to 4200 pairs of copper wires sheathed in paper. They are protected from moisture by air in the cables and must be inspected constantly for leaks. The new optical fibre cables now being gradually introduced by Telecom will, in turn, make all these copper wire cables redundant as they can carry 10 000 circuits.
It is a far cry from the lines used when the telegraph system was introduced to New South Wales during 1858. While that system only was in use there was comparatively little overloading of aerial construction for it was an Earth-return system and, in addition, there were few lines leading out from the city. However, it became a different matter when, in 1880, the telephone system was introduced to Sydney. There were ten subscribers connected to the first government telephone exchange, which opened in 1882. Ten years later this number had increased to about 1500 and, as the great majority of these subscribers were located in the city proper, it can be appreciated just what congestion there was.
There was a pole outside the GPO on the Pitt Street corner of the building, to which wires came in a short span from another pole on the spot which is now the corner of the Commonwealth Bank. From the pole on the GPO corner, the wires, some of them in aerial cables, entered the telephone exchange, through a small window on the Pitt Street end -the third from the corner -on the third floor. On these poles, there were no less than twenty-two double cross arms. There were poles everywhere and the air was literally filled with wires. The position was much the same at the George Street end of the building, where the telegraph operating room was located. On what is now the northern corner of Martin Place and George Street, was a pole with twenty double cross arms, from which aerial cables led to the GPO under the second arch from George Street. In front of the George Street end of the building were two iron poles arranged somewhat like the present day H pole. The iron poles were about three to seven metres apart at the kerbside and were connected on the top by an arch (to which insulators were attached). This very brief description of the situation, as it existed in the late 1880s and early 1890s, makes it clear why the authorities were forced to take some action.
A very small tunnel thirty-eight metres long, was constructed in 1887 across George Street from the GPO tunnel to the corner of David Jones's store. The total cost of the job was only f190. At this stage, little is known of the tunnel2, It is thought that it was built to carry the wires across to George Street, from whence they would be taken along the street towards Haymarket by -means of frieze-work, built along the front of shop verandahs. This was actually carried out for a while but was later demolished. It is recorded in a memo dated June 1897 that the frieze-work cables along George Street were becoming so bad that it was difficult to get through the telephone business (presumably new installations, and so forth). Something had to be done urgently. The small tunnel across George Street was about a metre in both width and height and constructed of bricks. It is still in existence, but not in use:
In the New South Wales Legislative Assembly on 25 November 1890, the Postmaster General informed a questioner that the Superintendent of Telegraphs was submitting a recommendation concerning the carrying of telephone and telegraph wires in tunnels. In 1892, another tunnel (which, for historical purposes, may be regarded as the first) was constructed from the GPO basement to the corner of Moore Street (now Commonwealth Bank corner) and from there to the corner of Moore Street and Castlereagh Street. Moore Street is now included in Martin Plaza. Martin Place, as it was known at that time, .extended from George Street to Pitt Street, having been opened for traffic on 5 September 1892.
The Town Clerk of the City of Sydney had written on 7 January 1892 to request that all wires up Moore Street should go in a tunnel. He suggested that the work could be conveniently carried out simultaneously with the formation of the roadway. This particular section of tunnel was commenced in March 1892 and completed in December of that year, at' a cost of £3330. The work, as was the case with most tunnel sections, was carried out under the supervision of Messrs. A.L. and G. McCredie, more commonly known as McCredie Bros. Architects, engineers and builders, they built the GPO and many other prominent city buildings. By way of remuneration, they received five per cent of the completed cost of the tunnel, for which they prepared plans and specifications and supervised generally.
THE ROYAL EXCHANGE TUNNEL
It was not until January 1895 that approval was finally given by the Postmaster General, Joseph (later Sir Joseph) Cook, for the construction of a tunnel from the GPO to the Royal Exchange Building via the eastern side of Pitt Street. Most of this work was eventually carried out by the open-cut method. A nib to the tunnel at Hunter Street was later built by day labour.
It should be remembered that the tunnels were not built in a straight line at all times and were deviated where necessary, to avoid other mains. The level of the tunnels was not constant either, for the same reason. There was also a great variation in the cost per running foot. The Pitt Street section to Royal Exchange cost £3 per foot while the Barrack Street section cost only £1 19s. 8d. per foot.
After the first couple of sections had been completed by contract, Joseph Cook decided to carry out the construction of any future section by day labour (contract labour hired by the day as opposed to staff labour), and to engage McCredie Bros. to supervise their construction. This decision had a far-reaching influence on the history of the tunnel network. For one thing, the contractors and builders of Sydney were quite naturally upset at this ruling by the Minister.
In 1895, George Donald was appointed Clerk of Works of the tunnel construction after being recommended by McCredie Bros. for the position. His salary was £4 per week and his first task was the GPO to Royal Exchange tunnel, a contract section. After day labour construction was introduced, he received £6 per week from December 1897, but it was reduced to £5 per week when the main sections of the tunnel were completed.
During the 1890s, there was a general recession and unemployment was rife. Many of the unemployed sought work on the tunnel construction and it was generally accepted that employment on the extension of the tunnel system was a form of relief work.
One of the problems associated with the building of the tunnels was the danger of causing the collapse of the foundations of adjacent buildings. There were several unsuccessful legal actions taken by city firms over this, so extra precautions were then taken. Before commencing a tunnel section, a thorough exterior inspection of the buildings along the route was carried out and all details of any structural weakness, cracks, etcetera were noted.
When day labour was introduced the City Council placed many obstacles in the way of the Postal Department, who were forced to make the tunnel by driving a shaft at all times instead of the open-cut method which all experts agreed was a better and cheaper way, when possible to use it. In some parts the top of the tunnel was only a metre -and sometimes even less -from the pavement level. This meant that extensive timber was necessary to carry out the task.
While the tunnel was being built along the eastern side of Pitt Street -between King and Park Streets -there were several minor subsidences. Complaints were made, of . course, by the City Council, and the matter was brought up in Parliament.
Eventually, a Select Committee was appointed and their deliberations extended over several days during July 1897. The evidence given before this Committee, proved that there was considerable opposition from builders and contractors to the Department carrying out such work by day labour; their contention being that it should be done by contract.
The Department eventually came out of the inquiry with great credit.
The George Street Extension In 1899 the Telegraph Department\-still had control of the building of the tunnels. An extension of the George Street tunnel was completed in 1899. This extended from the Railway tunnel along George Street West, on the southern side, to Glebe Road. It crossed Parramatta Road and ended just a short distance along Glebe Road. About three-quarters of this section was open cut, the tunnel varying in depth from three to seven metres. This
section was urgently required because of the heavy congestion of overhead wires. The terminus of the tunnel was then at the railway bridge at the Railway Station (then at Redfern)
at which point the tunnel was seven metres below the ground.
The cost of the tunnel construction from the date it was transferred to the Works
Department from the Telegraph Department in 1899 was £81 471. This would have been
approximate, though, because after completion there were claims for subsidence etc.
damage being submitted for some considerable time.
In the early days of the tunnel, cable was run with a specially-made drum mounted on a
truck, which was pulled along with a rope. In the early days of cable jointing in the city an
outside plumber completed the lead sleeve; later, each jointer completed his own.
It would seem that most, if not all, the city proper tunnels at least were built to the one specification. The bricks were of the one type and the construction in general was identical. Below the floor of the tunnel’s drainpipe -usually of thirty centimetres external diameter with the top of the pipe almost to the level of the floor -was placed for drainage purposes. The foundations of the tunnel were of a mixture. of five stone, one sand and one cement, with a floor rendering of one cement and two sand. The floor sloped from each side toward the centre. They were about a metre high and less than a
metre wide. There were a colossal number of bricks used in the construction of the tunnels. For the
800 metres of tunnel from the Royal Exchange along Bridge Street to Macquarie Street, 97 000 radiated bricks at forty shillings a 1000 and 91 000 square bricks at thirty-eight shillings per 1000 were ordered. In some parts of the city tunnels, some non-standard roof brickwork may be seen, which was caused by the non-delivery of radiated bricks; the square bricks were substituted as a matter of urgency. A rough calculation shows that there were seven or eight million bricks used on the tunnel network, the majority coming from the brickworks of Rupert Cook. Thousands of barrels of cement were purchased all of it imported, it is thought.
The wall bricks were square and were mostly wire-cut semi-plastic. This type of brick
was decided upon by McCredie Bros., in conference with Mr Cracknell in 1892, because it was necessary for them to be cut from time to time so that telephone connections could be
made. Radiated bricks (wider on the outside than inside) were used on the roof.
At intervals along the tunnel route there are manholes for access to the tunnel, most of
them being of cast iron with large lettered E.T.D. (Electric Telegraph Department) on
them. They vary in design and size. The greatest manhole depth is nine metres in Railway
Square, and perhaps the shortest depth is two metres in Pitt Street near Rawson Place.
Generally speaking the average depth of manholes was between three and four metres.
When the depth of the tunnel (two metres) is considered it may be seen that the top of the
tunnel was comparatively close to street level.
It may well be understood that the tunnel network displaced a huge amount of earth,
rock, and suchlike. The disposal of this spoil presented quite a problem, for it had to be
all horse-and-dray work. A lot was placed at Darling Island, some at Glebe Island Bridge, some at Saunders Quarry, Pyrmont, and some filled up a pond at the University near St John's College. Spoil from the Oxford Street section went to various government reserves in the locality including the Showground, the Cricket Ground and the old Rifle Range (which had been dedicated as a sports ground) and to the Friendly Societies' Ground at Moore Park. The Show Ground and the Cricket Ground made payment for it. Some also was supplied to Paddington Council to fill up one or two streets.
There was an unusual amount of worry for the department over labour problems. During the 1890s depression years, many hundreds of men were constantly seeking employment -in fact, the tunnel construction was regarded as relief work. Labourers were paid seven to eight shillings a day and the bricklayers usually got ten shillings per day. There was a constant stream of drays carting spoil from the tunnels, the rate of pay being equivalent to about eleven shillings a day out of which the man also had to feed his horse and maintain the dray. By 1900, the employment situation had improved considerably and there was a gradual increase of wages. Many of the men employed on the tunnel construction, whether carried out by contract or day labour, were miners. For most of the time, while tunnels were being built in the congested city streets, a night shift was employed so that business people would be inconvenienced as little as possible. At one stage, continuous working bas adopted by using three shifts.
There is no record of the number of men involved on tunnel construction. The number varied, of course, and at times, there were nearly 250. The number was naturally restricted.
Taking away rock in trucks in the Dalley Street telephone cable tunnel.
by the nature of the work -for example, in the driving of shafts, there was only space for one miner at the face. The Clarence Street section was one of the most difficult, being mostly through hard rock; all the crossings had to be tunnelled under, the remainder being by open cut.
Pumps and drainage
As early as November 1896 it was reported that water was percolating through the walls and floor of the Pitt Street tunnel at Hay Street. At this point, the tunnel had to dip under a sewer main, thus bringing it down to the tide level. The tunnel, therefore, had to be pumped out by hand every day. It was arranged for an "ejector" with self-acting tap, to be supplied and power supplied from the Water Board's main in Pitt Street.
The running cost, however, was greater than expected and the PMG Department was paying the Water Board over £1 a week. It was, therefore, decided to run wires from the GPO dynamos and provide an electric motor and pump at Hay Street, at a cost of about £160.
There was a very heavy storm during January 1901, which resulted in many lines being put out of action. The water reached the top of the Pitt Street tunnel at the King Street crossing where there was a depression, and the water backed up to the extent. that some ran through the Tunnel Test Room. There was also a big depth of water in the. George Street tunnel at Haymarket, which the hand pump could not cope with.
An earlier mention of a pump for the George Street tunnel was made in August 1900, when it was recommended that an electric pump should be connected to the "electric power mains in the Pitt Street, tunnel". It was envisaged to replace a hand pump fitted in the manhole at the corner of George and Hay Streets. This was approved and supplied at a cost of £72 in March 1901. ...~
At that time, W. Tolley of the Public Works Department was in charge of the construction of telephone tunnels and, in a report concerning the pump, he mentioned that there was a difference of about two metres in the levels of the tunnels in Ritt and George Streets. It was therefore approved that the Public Works Department should construct a drain from the Pitt Street tunnel to the George Street one, and eventually feed the drainage into the Darling Harbour low level sewerage. The drainage of the tunnels was in itself quite a problem. The levels of the tunnels did not permit of uniform gravitation because tunnel floors dipped at times to avoid obstructions, such as sewers. For example, some problems were met when the tunnel from Dalley Exchange to the Pitt Street section was built about 1950 as it cut across the Tank Stream area. Four automatic pumps had to be installed to cope with the flow of water.
In later years it became necessary to add further small sections to the network. With the widening of Oxford Street during 1911-12, the City Council built nine communicating tunnels about one metre wide and 1.3 metres high along Oxford Street, between Wentworth Avenue and Flinders Street. Others were built along Pitt Street, between Campbell Street and the railway in 1902, when the new Central Railway was in course of construction.
The building of the city railways during the late 1920s meant that further minor alterations had to be carried out but these, of course, were done at the expense of the railway authorities.
Major additions were made when Dalley Street Exchange was being constructed and a tunnel was built to 'link the Exchange with the Pitt Street section. Difficulty was experienced with this section because it crossed over the old Tank Stream bed.
Drowning and suffocation were among the hazards workers risked as they met unexpected difficulties in excavating across and under the course of the old Tank Stream. Rocks in dangerous formations frequently crashed down on them, and water from the long-buried course of the historic stream swamped them. Sweating engineers and workmen toiled day and night to hew out the tunnel carrying telephone lines to the new exchange. Time and time again the excavators had to dig deeper to bypass crumbling rock and the fast-flowing Tank Stream.
The tunnellers' next hazard was old, rotting. wharf timbers embedded deep in mudfilled cracks between the rocks. Engineers believe the timbers were once part of a bond store wharf which jutted out into the Tank Stream. The Tank Stream has an outlet into the Harbour beneath Circular Quay. The timbers had to come out because they stood in the direct path of the tunnel. They were chopped up and pulled slowly out of the embryo tunnel then only a metre wide and high. As workmen levelled off the tunnel at about ten metres below Dalley Street, water in alarming quantities seeped in. The tunnellers were heading straight for the Tank Stream, only a few metres away.
Their pneumatic drills nibbling at the hard rock, the diggers dipped again, this time to about ten metres and only a small distance below the Tank Stream's bed.
The going got even tougher. The tunnel was so small that workmen had alternately to crouch and lie flat to work. Miners' helmets protected their heads from dislodged pieces of rock which frequently crashed down. Stagnant water and oozing mud slushed above their knees. And always there was the nerve-racking drip-drip of water from the Tank Stream bed above on to their bared backs.
A workman could swing his pick only a few centimetres in the oppressive atmosphere. He would spend as much time back on the surface gulping in fresh air as toiling down below. Heavy rainfalls and high tides kept the Tank Stream rising and falling unpredictably. Only small explosive charges could be used. Supporting beams in extraordinary number had to be rigged close together. Several times a workman's pick struck a weak rock patch and water poured in. Many times workmen crawled with desperate haste out of the tunnel within seconds of water reaching the roof, after which work would be delayed for days until the pumps had drained the tunnel and engineers had plugged the leakage.
The tunnelling under the Tank Stream took nearly six months to complete.
Beneath the Exchange tunnellers had to skirt crazily around a maze of street sewerage 1and drainage pipes. When the tunnel was finished thousands of tonnes of concrete were steam blasted on to its interior. A private firm sealed off the area beneath the Tank Stream with a special cement mortar and water proofing compound.
Finally, the job had been completed.
Telephone cable tunnels are labelled with signs telling workmen where they are.
This photo shows cables outside the Commonwealth Bank in Pitt Street.
|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.|