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Introduced in 1927, this wooden electric passenger car was one of many which ran on the Sydney metropolitan system up until the late 1960s. (Bryan Maher photo). 'l'H E EVOLUTION OF ELECTRIC RAILWAYS As in other countries, Australia had some experience with electric traction before the turn of the century. However, it was not till much later that extensive electrification took place. By BRYAN MAHER suburbs. Expanding gradually, the Railways Department built and operated a large system of high voltage feeders from their power stations to many country towns and cities. They used 33kV lines from Newcastle to the Hunter River Valley and up the north coast towards Grafton; 66kV lines fr om Sydney to the Blue Mountains; and also Australia's first intercity power line interconnector, the 66kV line built in 1942 to join Newcastle and Sydney. One of the spans of that Newcastle-Sydney interconnector was a record 960 metres long, across the Hawkesbury River. This particular span was believed to be the longest power line span on wooden poles in the wo r ld . Originally built using 19-strand 10 gauge cadmium-copper conductors, that span with a 61-metre sag in the middle had each phase supported by a pyramid structure made of three 18 metre wooden poles sunk 4.3 metres into the rocky hilltop. The whole 66kV line fro m Hamilton substation in Newcastle to St. Leonards substation in Sydney was designed to carry 200 amperes, and at full current 6000 The absolute first electric traction of any type in Australia was an electric tramway using a direct current overhead trolley wire system in Sydney, from Waverley to Bondi Junction. This came into operation on 9th November, 1890. Direct current supply was generated by the New South Wales Railways at an installation a small distance away in the direction of Randwick. That little DC generator near Randwick marked the first entry into t h e electr icity generating business by the New South Railways, starting an enterprise which continued to grow for the following seventy years. The Railways Department during that time not only generated all power used by electric trams, trains, stations, yard lighting, workshops and signals in the Newcastle, Sydney and Blue Mountains districts, but also supplied, owned and operated at Newcastle the largest electric and hydraulic coal loading wharf system on the Pacific Ocean. Furthermore, in that period, the New South W ales Ra il ways operated 50Hz and 25Hz coal burning power stations at Ultimo and White Bay in Sydney and at Zara Street in Newcastle, and for a long time owned some of the largest synchronous motors in Australia 10MW in Newcastle and 30MW in Sydney. During that time, the Zara Street plant also supplied 90 percent of all power used in Newcastle and its - -_ ELECTRICS IN AUSTRALIA 76 PART 5 S ILICON CHIP volts was lost over the length by resistive losses. This was the first time in Australia that two large cities had their power systems synchronised and joined. Victorian Electrics Melbourne became the first Australian city to boast electric suburban trains, in 1918. Some wooden carriages, previously steam-hauled, were converted to electric traction by the fitting of pantographs, control gear and new bogies containing electric motors. Overhead wiring construction was proceeding on a number of suburban lines and the first electric train, from Sandringham to Essendon, ran in 1919. Construction of AC-DC substations and overhead conductors above the tracks continued and Melbourne's 1500 volt DC electric suburban railway system eventually grew very large. Australia's early use of electric locomotives was confined to the coalfields in the eastern corner of Victoria where the very considerable brown coal deposits are mined by the open cut method. The first electrically hauled coal train ran in 1923. The Melbourne Electric Tramway system has, since quite early days, been working with the railways in shifting millions of commuters. Nowadays, this system is the only extensive electric tramway system remaining in Australia. A shining example to the rest of Australia, Melbourne has extended the tracks and purchased many new tramcars. The up-to-date "Z" class, of which 215 new cars have been put into service over a ten year period, are now being augmented by the latest order of 52 modern "A" class trams. In 1985, a $100-million contract was let by Melbourne's Metropolitan Transport Authority for the supply of 130 Articulated Light Rail Vehicles for use on long tram routes and later on two converted railway routes. These advanced vehicles consist of two cars sharing three bogies. Propulsion is by two 600 volt DC 195kW AEG traction motors. These can speed the 32.5 tonne vehicle with its 182 passengers along at a brisk 72km/h. The modern control system uses Grand old Locomotive No 1, the first steam loco in NSW. This beautifully restored loco is on permanent display in the Sydney Powerhouse Museum. (SRA photo). AEG thyristor DC-to-DC chopper circuits. Melbourne showed the world that construction of 1500 volt DC underground railways was still alive and well by opening their City Loop Line in 1981. Circling the City from Spencer Street Station via Flagstaff, Museum and Parliament Stations to Flinders Street or outer suburbs, this new line takes passengers within walking distance of their city workplace, easing street traffic congestion. Adelaide's longest surviving electric tramway, the famous fast Glenelg Tram has always been an example to Australia of the quickest way to move people. And the people of Brisbane were for many years served well by an electric tramway installation which reached the peak of its importance about 1930. Sadly, Brisbane eventually followed the lead of many other cities and scrapped all electric trams in favour of diesel buses. Newcastle and Sydney To appreciate the early story in Newcastle and Sydney we have to keep in mind the intimate relationship in New South Wales between the railways, tramways, power stations and coal loading wharves. These were all administered by the Department of Railways. Electric tramway systems had been expanding since their beginning in 1890, long before electric trains appeared. Newcastle was originally founded because a certain British Army lieutenant saw coal protruding out of the ground between Cooks Hill and Merewether while he was out chasing escaped convicts. With a working railway from Newcastle tci East Maitland from 1857, the discovery of large deposits of Australia's best gas-coal over an area from Walls end to Cessnock opened the possibility of an export market as a permanent boost to the colony's finances. Seizing the opportunity, the New South Wales Railways built the largest coal loading wharves in the country on an unused expanse of low-lying land known as Bullock Island on the north side of Newcastle harbour. Initially, five hydraulic coal loading cranes were installed, later extended to thirteen. Before the turn of the century, and for many decades after, Newcastle was the greatest coal loading port on the Pacific Ocean. So many sailing ships called at the port that while awaiting loading they were tied up three deep over miles of wharves. MARCH 1988 77 This was one of the 500 horsepower 6.6kV motors which drove the centrifugal pumps for the hydraulic cranes. These were used for coal loading at Newcastle. (Bryan Maher photo). To handle all the coal trains, the New South Wales Railways built the largest railway yard in the Southern Hemisphere. Complete with four weighbridges the whole installation, including storage and loading yards, was seven kilometres long. Running through five suburbs, the storage section reached sixty tracks wide, capable of taking 200 fully-loaded trains. Coal loading The hydraulic cranes installed for coal loading used water as the working fluid at a pressure 700 psi. The original steam-driven pumps were augmented in 1914 by two electric motor driven 3-cylinder piston pumps. The 600 volt DC 200 kilowatt compound motors were designed to start and stop automatically to keep up the supply of high pressure water as required by the cranes. Much later, in 1943, a fourteenstage centrifugal water pump driven by a double-ended 500hp (373kW) three phase 6600 volt induction motor was added to augment the hydraulic system. About 1914, the coal loading facility received a boost with the addition of seven huge electric cranes each weighing 240 tonnes and capable of lifting 15 tonnes. These were equipped with twin 75kW hoist motors and 56 kilowatts each for the travel and slew motors, on 600 volts DC. The Bullock Island 600 volts DC system grew in useage and was inter c onne cte d to the growing Newcastle suburban electric tramway system. To provide the required 600 volt direct current for all these loads, a 600 volt 3000 amp DC rotary converter was installed in the substation. Also provided were 300 lead-acid cells, each big enough to have a bath in. These constituted a 600 volt battery capable of providing 1000 amps of load current for hours (sometimes all night) if and when the AC supply or the substation were shut down. A rotary converter resembles a large DC generator with commutator and brushes but with the addition of tappings from some armature coils. These taps are connected to slip rings and are fed with AC, usually 6-phase, supplied from a 3-phase transformer. The converter runs at a synchronous speed determined by the AC frequency and the number of armature poles while DC output is delivered from the commutator and brushes. It is an efficient and compact machine, superior to an AC motor driving a separate DC generator. Because rotary converters work better with low frequency AC, all NSW Railways power stations generated 25Hz 6600 volt AC for traction supply, and separately generated 50Hz 11,000 volt AC for lighting and other loads. A very strange machine A 33-class loco shunts long lines of coal wagons at the Newcastle loading docks in the 1940s. The hydraulic cranes can be seen in the background. (Bryan Maher photo). 78 SILICON CHIP Other Newcastle tramway substations, each containing two 25Hz AC to 600V DC rotary converters, were built at Hunter Street and Hamilton. This latter substation supplied 600 volts DC to Newcastle's southern and western suburbs, the most distant being Wallsend, 13km from the city. Con- "to shoot through like a Bondi Tram." Electric trolley buses were introduced on a limited scale in Sydney near Town Hall and in the suburbs of Kogarah, Rockdale and Brighton-Le-Sands. These clever machines used two trolley poles contacting both a positive 600 volt and a zero potential overhead contact wire. Capable of being steered on any part of the road, these rubber-tyred vehicles called at the kerb for passengers and their quiet operation and fast acceleration distinguished them from diesel buses. At crossovers and junctions the construction of the oppositepotential parallel trolley wires was quite a headache. The Balmain beautie An earlier motor used to drive hydraulic accumulators at the Newcastle dockyards. Installed in 1914, it ran on 600V drawing 386 amps. (Bryan Maher photo). diderable voltage drop occurred along the long 600 volt feeder cables. To compensate for this voltage drop a rather strange machine called a Direct Current Series Generator was added at the Hamilton substation. This generator was driven at constant speed by a 3-phase AC motor. Now a series DC generator (ie, a DC generator with its field coils in series with its own armature) has a very strange and somewhat unstable voltage/current characteristic. When driven at constant speed such a generator's output voltage is more or less proportional to its own load current. If we draw no current from it, this generator will generate almost no voltage at all. If we draw a small current from it the machine will generate a small voltage and if we draw a large current, this same machine will generate a large voltage. Now that series generator was itself placed in series with the 600 volt feeder supplying trams which were out at the end of the W allsend line. With the rotary converters generating a constant 600 volts, the series generator added extra volts proportional to tram current, extra volts intended to be just equal to the voltage drop along the cable, so that the correct 600 volts always appeared at the other end. In peak hours, when trams at the end of the line could take as much as 500 amps, up to 300 volts was added to the system 600 volts, making 900 volts in all at the substation end. If we now subtract the 300-volt drop along the long cable due to its resistance, we get 600 volts out in the distant suburb, so the tram and passengers were all happy. Do you believe it? Yes, it really did exist. Theoretically minded readers will see it as a case of a positive resistance (the feeder cable) being cancelled by an equal negative resistance [the series generator) of - 0.6 ohms. Wow! Sydney electric tramway Meantime, back in Sydney, the electric tramway system was growing too. It also ran on 600 volts DC and a similar system of rotary converters in DC substations was built at strategic points of the suburban system. But whereas Newcastle trams were propelled by two motors, one in each bogie, many Sydney tramcars were equipped with four motors, to cope with the hilly terrain. These gave good acceleration on level streets and led to the world-famous Australianism Many Sydney harbourside streets feature a "steep-drop-tothe-water" but do readers recall the remarkable installation once used to allow trams to safely-descend the hill to Balmain Wharf arid then make the very steep ascent back up again? The tram's traction power and rail adhesion were insufficient for this short steep climb. Therefore, below the road, right under the tram tracks, was constructed a tunnel on the same slope as the road. In the tunnel was laid a standard gauge rail track upon which ran a heavy four wheel truck weighing about 12 tonnes. Up above, on the tram track, was mounted a strong but light four wheel truck. These two trucks were tied together by a long heavy steel cable, the steel cable passing over a pulley mounted just below the road surface at the top of the hill. You can work out what happened, can't you? Left to themselves, the two trucks rested with the heavy truck in the tunnel at the bottom of the hill, and the light truck sitting all alone on the tram track in the middle of the street at the top of the hill, held by the steel cable. So any attempt to push the light truck downwards on the tram track meant pulling the heavy truck up the track in the tunnel below. Of course the tunnel and the heavy truck in it were completely hidden from view. All that was visible was that silly looking light truck MARCH 1988 79 To provide a 600V DC supply for the Newcastle dockyards, a 3000 amp rotary converter was installed, in conjunction with a 600V battery capable of supplying 1000 amps. The small motor on the shaft was used for starting. in the middle of the road. Just imagine it. Along comes a d·ouble tram wanting to go down the hill to the wharf. It stops at the top of the hill and slowly nudges forward till it meets the light truck sitting on the track in front of it. The tram then drives forward, pushing the light truck down the hill and in so doing pulls the heavy truck in the tunnel to the top of the hill. Meanwhile, at the wharf, a Sydney ferry arrives and disgorges hundreds of weary city workers. All climb aboard the double tram which then starts up the hill, traction motors working hard and with the light truck now pushing from behind because of the weight of the heavy truck in the tunnel. The combined effort of tram's motors and the truck push is sufficient to haul the tram and its 200 tired passengers to top of hill. Success. Sadly, Sydney decided (followed by Newcastle) to scrap all 600 volt DC electric trams, to be replaced by 80 SILICON CHIP diesel buses. All tram tracks, overhead wiring and substations had to be demolished. The destruction, begun in the mid 1940s, pleased some and disturbed others who saw electric trams as the quickest way to move large crowds at important public events. Two clever machines The Railways also used the 600 volt DC system to supply cranes in the large railway workshops at Everleigh and Chullora in Sydney. A similiar system supplied cranes in the Newcastle area at Cardiff Locomotive Workshops, Honeysuckle Point Rail Shops, and the Bullock Island coal loading depot. So at least some 600 volt DC rotary converters survived for a few more years. Because Cardiff Workshops were built out of Newcastle, too far out to be supplied at 6600 volts AC 25Hz, use was made of the 33kV 50Hz AC ring main from Hamilton- Cardiff-Maitland. This presented a design difficulty for the Cardiff 600 volt DC substation as rotary converters suffer bad commutation and brush arcing if run on 50Hz supply. To solve this problem, a pair of very clever machines called Motor Converters were installed, each rated to deliver 600 volts at 500 amps DC. These machines had an AC stator winding supplied with 2200 volts 5GHz 3-phase AC. This induced currents in the rotor by ordinary induction motor action except that the rotor ran at exactly half synchronous speed. This resulted in rotor currents being half frequency, ie 25Hz. The stator was extended to carry a set of DC compound field coils and the long rotor had a commutator connected to all rotor windings at that end. DC output was collected from the commutator by brushes in the same manner as rotary converters. With only 25Hz currents in the rotor, commutation was perfect in these machines. It can be shown that half the output energy was derived by motor generator action and half by rotary converter action, and that the efficiency was higher than a straight motor generator but lower than a simple rotary converter. Advances in coal loading The State Rail Authority in 1961 moved out of the coal loading business at Newcastle, that industry being taken over by the Port of Newcastle (part of the Maritime Services Board). Two of the electric coal loading cranes, Nos.12 and 13, with their 29-metre high jibs were retained for loading of general cargo, while all other cranes were removed. All coal loading is now performed by fast belt convevors, capable of delivering up to 10,000 tonnes per hour. The new wharves are suitable for ships up to 229,000 tonnes and 15.5 metres draught. Of the once-remarkable hydraulic crane system, all has passed into history except the handsome solid stone Hydraulic Power House building, listed by the National Trust. Next month we will have a close look at some DC electric railways.