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PT.6: THE SYDNEY AND BLUE MOUNTAINS SYSTEMS THE EVOLUTION OF ELECTRIC RAILWAYS In this episode, we look at one of the cleverest applications of electrical inventiveness in railway history - the Sydney suburban and Blue Mountains systems. By BRYAN MAHER As all Australians well know, the economic success of our nation depends heavily upon the inland graziers, farmers and miners. Their products must be carried to the coastal ports for export and their machinery and other manufactured requirements need to be transported back to them from the cities. Unit trains (ie, those carrying only one commodity such as wheat} are the fastest and most economical method of shifting large peak loads. In Western Australia, South Australia, Victoria and Queensland this transport presents no speciai problems. But in New South Wales the story is quite different. From the north and north west regions to the wheat, coal and wool port of Newcastle, the Great Dividing Range must be crossed at Ardglen near Murrurundi by a difficult single track climb. If proceeding further south to Sydney, the eight kilometre climb known as the Hawkesbury Bank from Brooklyn to Cowan must be conquered. This continuous heavy 2.5% grade required two or three steam locomotives on every train. An even worse situation existed on the western line. Climbing the Great Divide between Bathurst and Lithgow was no great shakes but the assault on the Blue Mountains was quite a different "kettle of fish". Travelling eastwards from Lithgow the line rises 58 metres in the first 2400 metres of track length. Then, climbing another 100 metres elevation in the next 11.5 km, trains must negotiate ten tunnels up to 786 metres long and reverse curves as sharp as 161 metres radius as they cling to the side of the mountain. The peak elevation of 1067 metres (3500ft} above sea level is reached at Mount Victoria. Wheat and wool trains from the Western Plains and unit coal trains from the western fields all vie with express passenger traffic for space on this line. The big climb A 1928 MODEL SYDNEY SUBURBAN parcel express van. The vehicle weighed 50 tonnes when laden and its 537kW motor gave it excellent acceleration. (Picture courtesy SRA, NSW). 74 SIi.iCON CIIII' In the reverse direction, traffic from Sydney has an easy run to Penrith and Emu Plains then abruptly attacks the Blue Mountains as trains climb 300 metres (985 feet} in the first 18. 7km on a continuous 1-in-60 grade. From Valley Heights, the next 32km of track rises 692 metres (2270 ft} with grades varying from 1-in-47 to as steep as 1-in-33. Add to this the many tight radius reverse curves and you have one of the most difficult railway routes in the world. Passenger traffic is heavy, especially on the eastern side of the mountains. As well as the intersla te, country mail. express and fast XPT trains to such cities as Balhursl, Bourke and Perth . there A 57-CLASS 3-CYLINDER STEAM LOCOMOTIVE attacks the Blue Mountains' grades during late 1956. As this photo shows, the 1500 volt DC wiring is in position above the tracks but full electrification had yet to be completed. (SRA, NSW photo). is also considerable tourist and daily commuter usage. As early as 1949 the NSW Government realised that the existing track load of 54 trains per day each way was almost the saturation limit as freight trains were spending half their time standing in sidings to allow passenger trains to pass. In the foreseeable future, that figure would have to be increased to more than 70 trains in each direction each day. Something had to be done. A 1950 study considered five alternatives: (1). Use larger steam locos; (2). Replace the existing steam locos with large multiple unit dieselelectric; (3). Quadruple the whole track from Sydney to Lithgow; (4). Electrify the line from Sydney to Lithgow using high voltage AC or 3kV DC; (5). Electrify the line from Sydney to Lithgow using 1500 volts DC. Proposal (1) was found to be impossible because of the many very sharp curves while proposal (2) was ruled out because of the poor power-to-weight ratio of the large diesel-electric locomotives of the day (109 tonnes for a 1.34 Megawatt (lB00bhp) unit or 12kW per tonne of locomotive). Other designs were as low as BkW per tonne. With diesel-electric locomotives a large diesel engine drives a generator and this then drives electric traction motors which mechanically drive the wheels . The diesel engine, generator and diesel fuel add much unproductive weight. Calculations showed that on a 1-in-33 up-grade at 56km per hour, approximately half the locomotive's power would be used just in lifting the loco itself up the mountain. Proposal (3) would, if possible, allow freight trains to continue slowly up the mountain while faster passenger traffic passed on a dif- ferent pair of tracks. Such a solution was clearly impossible as parts of the Blue Mountains ridge are so narrow that there is really only room for the existing double track, the parallel Great Western Highway and a few houses. That left electrification as the only workable solution. The choice of "AC or DC and what voltage" was the subject of considerable engineering consideration. Proposal (4) investigations showed both 25kV AC and 3kV DC electric locomotives and multiple-unit passenger trains to be more expensive than the 1500 volt DC alternative. But the real killer of the high voltage proposal was the height of the eleven tunnels. This was inadequate for the long insulator strings needed for high voltage overhead wiring. Furthermore, many of the tunnels continually seep water and leakage or tracking across wet high voltage insulators could be a serious problem. Al'Il/L 1988 75 THE SECOND GENERATION SYDNEY SUBURBAN electric trains were single deck models with improved doors and lighting. The eight 269kW traction motors (2.15MW total) gave these trains remarkable acceleration. (SRA, NSW photo). Another disadvantage of both the 25kV AC and 3kV DC proposals would be the difficulties in joining the mountain system to the existing 1500 volt DC Sydney suburban system which had been in service since 1928. Proposal (5), to electrify at 1500 volts DC, was the only workable solution. This would require heavy copper cables for all overhead wiring and twin pantographs on all locomotives for current collection at thousands of amperes. Furthermore, to keep line voltage drop within acceptable limits, trackside DC substations would be needed at close intervals. Of course, there was the advantage that connecting to the existing Sydney suburban electric system would involve minimum expense. At this point we need a flashback, giving a summary of the salient points of the Sydney suburban electric system. So, gentle reader, let us do just that. Sydney suburban electrics During the 1920s considerable planning was in hand for the City Circle underground and for the 76 SILICON CIIII' electrification of the whole suburban system. Accordingly construction of overhead wiring, feeder cables and electricity substations proceeded apace. With concurrent work on many lines, the honour of being first went to the Illawarra line when the first electric train in New South Wales ran from Central Station through Sydenham and Hurstville to Oatley on the Georges River on 1st March 1926. Within five months the electric system was extended to Sutherland. By 1928 electric trains were running to Parramatta and shortly thereafter to the North Shore via Strathfield and Hornsby. Substations to provide a 1500 volt DC supply for the trains were built beside the tracks at many points within system. All those within the inner circle - Argyle, Sydney, Lewisham, Strathfield, Hornsby, St. Leonards, Parramatta, Sydenham and Hurstville - used transformers and rotary converters to convert 6600 volt 25Hz 3-phase AC from the Railway Power Stations to 1500 volts DC. The largest of these substations was Prince Alfred, just south of Central Sta- tion. Known as "P.A." this substation was equipped with four huge 1500 volt DC 4.5MW rotary converters. Later substations in suburbs further out, such as Regents Park, used water-cooled mercury-arc rectifiers fed via transformers from 33kV 50Hz 3-phase AC. February 1932 saw the first train leave Central, go under the City via the previously unused leftmost tracks, and race through the tunnels to the brand new Town Hall station, after which the train terminated at Wynyard. The Harbour Bridge was opened the following month, allowing trains on the upper level at Wynyard to continue on up into the daylight, and over the Bridge, to join the existing line to Hornsby. Fast train turnaround During peak hours the timetable demanded fast turnaround of trains termina ting and restarting at Wynyard lower level platforms. The driver literally did not have time to walk to the other end of his train. After off-loading passengers at the arrival platform, a train would run northwards into the Quay tunnels and stop. The driver would leave his train while simultaneously another driver would board the other end of the train and drive it back via the Wynyard switching tracks to the outgoing platform. There the train would be refilled with peak hour passengers, and be off to distant southern suburbs. Such organisation helped the Sydney underground system to achieve a remarkable daily peak hour traffic density of one train every 47 seconds. Train details Sydney's suburban electric system is based on the concept of eight-car trains although four-car trains are commonly used in offpeak hours. The standard makeup of a fourcar set is a power car at each end and two trailer cars in the middle, each power car having a driver's control cabin at one end only. From the start, each power car was equipped with a non-motor (or trailing) bogie at the driver 's cabin end and a motor bogie containing two traction motors at the opposite end. Mounted on top of the car at the motor bogie end, an insulated pantograph picks up current from a 1500V DC overhead copper conductor. Power from the pantograph is taken down to the underside of the car to the high voltage contactors, thence to the motors in the motor bogie. Each power car in a train picks up its own high voltage power from the overhead contact wire, so that only control circuits are connected from car to car for the full length of the train. Quite sophisticated for their time, the original 1926 control circuit designs used 32 volt DC electropneumatic contactors to control the high voltage motor circuits. The driver's hand-operated master controller at the front end of an eight car train can easily ca rry enough 32 volt current for all the motor control circuits in all four power cars. The driver's controller has four starting/running positions: (1). The low speed first step causes both motors in each motor bogie and a bank of cast iron starting THE NSW SRA INTRODUCED THESE double-deck inter-urban trains on the Blue Mountains run in 1970. Designed and built by Comeng of Granville, these 1500V DC passenger trains are lighted and air-conditioned by an on-board 415-volt 3-phase auxiliary power supply. (SRA, NSW photo). ·-~'.l... ···- •' ~ ~ - - THE 46 CLASS WAS THE FIRST production electric locomotive used in NSW, commencing service in 1956. This locomotive weighed around 110 tonnes and employed six 478kW traction motors, giving a total of 2.865MW. (SRA, NSW photo). resistances to be connected into one series circuit. (2). The second step engages an "acceleration relay" which senses traction motor current and automatically closes a "notching" contactor when acceleration brings motor starting current back down to 160 amps. This contactor bridges out part of the sta rting resistance, accelerates the train further and raises motor starting current again. When more acceleration brings motor current again down to 160 amps, the next notching contactor is automatically closed, bridging out more of the resistance and thus causing further acceleration. This automatic process continues until all the sta rting resistance is bridged out, leaving the pair of motors in series. (3). The third step connects both motors in pa rallel but in series with the starting resistance. Again the acceleration relay senses motor current and progressively closes notching contactors. cutting out 1\1'/lll. lfl8 /l 77 and that the cars were built in Australia, we begin to appreciate the expertise of earlier years. Motor details INTRODUCED IN 1979, THE SRA CLASS 85 is a CoCo type 1500V DC electric locomotive with an output of 2.88MW. It weighs around 123 tonnes and is capable of speeds up to 130km per hour. (SRA, NSW photo). sections of the starting resistance until the motors are in "full parallel" directly across the 1500 volt supply. (4). The fourth step leaves the motors in "full parallel" but shunts the motor series fields with resistance, thereby reducing motor field strength. This causes the motors to accelerate to still higher running speed, the design maximum being 80km per hour. The driver may leave his controller on any one step or may start from a station by moving his con- troller directly to the highest step, in which case the four steps described will automatically be followed by the equipment in proper sequence. This added safety feature meant that the driver could concentrate on driving and forget electro-mechanical details. As well, the design can make use of the maximum acceleration without wheel-slip on every start, an especially useful feature on the "all stations" runs. When we recall that this level of sophistication was designed, up and running by 1926, The original design specified two axle-hung 1500 volt DC four pole series 360hp (269kW) traction motors with interpoles for each motor bogie. Thus the four power cars of an eight-car train contain between them eight motors totalling 2880 horsepower or 2.15 megawatts. No wonder they can scarper out of the stations. Also each power car is equipped with a 1500 volt DC motor driving an air compressor, and batteries providing 32 volt DC supply for control and lighting, charged by a motor-generator set. New cars were all steel single deck units, the power cars weighing 50 tons, the trailer cars less, giving the original design acceleration figure of 2.08km/h per second. Braking The initial design featured direct air braking using cast iron brake shoes and the repeated stopping of an all-stations train could wear out a full set of brake shoes in a week. As well as the cost of their constant replacement, the clouds of cast iron dust generated when stopping permeated everything. Fitters and other running shed staff continuously engaged in working under trains sometimes found the cast iron dust even entered the pores of their skin, staining clothing many hours later. A later change to plastic composition brake shoes reduced the wear and dust problem but required increased pressure of shoe against running wheel to compensate for the reduced coefficient of friction. Also, as these shoes polish the wheel running surface, the acceleration rate had to be reduced to prevent slipping during starting. Automatic stops THE LATEST SRA LOCOMOTIVE is the 119-tonne 2.88MW 86 class, introduced in March 1983. Fifty of this class have been added to the SRA's fleet. (SRA, NSW photo). 78 SIUCON CIIII' Where tracks approach points, crossovers or junctions, the signals protecting these are equipped with an electro-mechanical arm unit mounted on the track sleepers. When the signal is at STOP (ie, redover-red), the electro-mechanical arm is raised and will hit a small brake trip arm mounted on the left side of the front bogie of every train, shutting off motor power and applying full brakes should any train attempt to run through the stop-signal. An extra safety feature is that the driver must rest the weight of his hand on the controller handle at all times otherwise the train is automatically brought to a stop. Keep in mind, gentle reader, that the basic design of Sydney's suburban system worked out in 1925 proved so successful, both in terms of safety and in density of traffic carried, that no reason has been found to make changes, apart from those brake shoes on the trains and the use of 6-phase mercury arc rectifiers rather than rotary converters in the latest DC substations. By 1953, there was a total of 480 kilometres of track electrified and fed by 18 DC substations. That was the situation in the early 1950s when railway engineers were designing the Blue Mountains electrification. Surely it was a sound engineering decision to extend electrification at 1500 volts DC across the Blue Mountains. Blue Mountains design Because the heaviest trains are those travelling in the eastward direction, and because they drop 1067 metres (3500 ft) in descending the eastern side of the Blue Mountains, full regenerative braking was adopted. This is a system wherein the descending locomotives use their traction motors as generators to feed current back into the overhead wiring to assist other trains which are simultaneously ascending the mountain. Ascending trains using this regenerated current place a load on the descending train's motors [now acting as generators). This loading has a braking effect on the descending train, thus reducing its speed. By using this continuous, steady, even braking method, descending trains do not need to use their air brakes at all, saving wear in the train's many cast iron brake shoes and almost eliminating the cast iron dust menace. However trains still remain fully equipped with air brake systems, TABLE 1: LOCOMOTIVE WEIGHT AND POWER Year Loco Class 1926 1949 1949 1952 1952 1956 1958 1960 1962 1969 1979 1982 1983 1984 1986 1986 1986 Suburb. Elec. Steam Steam DC Elec. DC Elec. DC Elec. Diesel Elec. Diesel Elec. Diesel Elec. Diesel Elec . DC Elec. Diesel Elec. DC Elec. AC Elec. Diesel Elec. AC Elec. AC Elec. NSW 58 38 71 L 46 USA 49 45 422 85 81 86 9E G 3000 3500 Notes: (1 ). The (2). The (3). The (4). The Rall (HP) Rall (MW) Weight (tonnes) 0.537 720 50 2475 1.846 228 2250 1.678 201 2700 2.014 108 2400 1.790 98 3840 2.865 108 1350 1.007 120 0.650 875 80 1800 1.340 111 2000 1.490 108 2.880 3859 120 3000 2.240 126 3859 2.880 117 5067 3.780 168 3000 2.240 128 3887 2.900 109 3887 2.900 109 kW per tonne 10.74 8.09 8.35 18.65 18.27 26.52 8.39 8.13 12.13 13.80 24.00 17.78 24.62 22.50 17.50 26 .60 26 .60 "G" and "L" class are Victorian. "3000" and "3500" class are for Queensland coal trains. "9E" class are South African 50kV locomotives, 3ft 6in gauge. "Suburban Electric" figures are for one Sydney power car. both for emergencies and for bringing a train to a complete stop. As Table 1 shows, in 1956 the power-to-weight ratio of 1500 volt DC electric locomotives was more than three times higher than any contempory steam or diesel-electric type and even today the electric locomotive still wins in this regard by a factor of 35%. Therefore, the electric locomotive uses less of its power lifting itself up the mountain, leaving more useful power to haul the train up the difficult climb. The result of the electrification of the Blue Mountains is that trains even freight trains - race up the mountain at remarkable speeds considering the gradient. Fast freights running at passenger train speeds now spend little or no time standing in sidings waiting for passenger trains to pass, resulting in a doubling of the possible number of trains per day. Between 110 and 120 trains per day now ascend or descend the mountain. Train running time was reduced by electrification from the previous 138 minutes to 74 minutes for the trip to Mount Victoria. For freight trains, 2 hours 30 minutes was sliced off the running time while at the same time maximum loads c_arried have been doubled. Also the journey down the mountain is faster under smooth steady regenerative braking compared to the older periodic application and release that was necessary when using air brakes on long descents. Use of regeneration current by other ascending trains results in 20% less electricity used from the substation. The quantity of traction electricity used can be calculated in terms of coal burnt in the distant power station. The quantity of coal so needed by the power station per electric train is about one tenth that burnt in steam locomotives per train under the old system. This amounts to 150,000 tons of coal saved per year. Locomotive design The electric locomotives chosen were manufactured by Metropolitan Vickers Ltd of England and named the " 46" class. 40 of these machines were made, the first being run on the line on 25th June, A l'!llL '1988 79 1956. The locos and the overhead wiring were designed to allow for double heading, with triple heading provided for on the steepest grades. The 46-class locos used six-wheel bogies with each axle driven by its own traction motor. The six traction motors are Metropolitan Vickers 6-pole series type with interpoles, each motor rated at 477kW (640hp). All traction motors and running wheels run in roller bearings. The motor armatures are lap wound and arranged to run on 750 volts DC. The six motors in each locomotive are arranged to run as three parallel pairs of two motors in series. For low speed running they are switched to two parallel triplets of three motors in series and for starting they are switched to all six motors in series. Starting resistances are also switched in series with the motors, such resistances being progressively bridged out in 19 steps called "notches" by high voltage contactors operated by the driver 's controller. These control circuits are extended by jumper cables to the second (and third) locomotive for double or triple header operation. A circuit of relays and bridge resistors continually tests the equality of voltage drop across pairs of motors. Should one pair of driving wheels begin to lose traction and slip (such as on wet rails), the motor driving that axle becomes mechanically less loaded and hence has less voltage drop across it than the other motors. The relay circuit then informs the driver visually and audibly of this condition. The locomotive fleet wa s aug- SUBURBAN ELECTRIC TRAINS have carried millions of passengers across the Sydney Harbour Bridge since its opening in 1932. (SRA, NSW photo). mented in 1979 by the 85 class electric locos. These were followed by the "86" class in 1983, 50 of this latter class eventually being added to the fleet. The tourist and commuter traffic is now handled by double-decked air-conditioned multiple unit electric trains. Parallel work on the Sydney suburban system resulted in double-decked trailer cars in 1964 and complete double decked suburban electric trains by 1968. By 1984 the electrification of the main line from Newcastle to Sydney was completed and today electric passenger and freight trains also operate from Sydney to Wollongong and Port Kembla on the Illawarra line, all of which use the same 1500 volts DC system. Victoria Other DC electric railways in -----====---' ~- t!~ I', f □ Australia are the extensive Melbourne suburban passenger system, which uses 1500 volts DC, and the V-line electric locomotives for coal and freight in Gippsland in Eastern Victoria. Here the " L" class electric locomotives, also operating on 1500 volts DC, are CoCo type; ie, two six-wheel bogies with all axles driven. The six traction motors are English Electric Type EE519 , each rated at 298kW (400hp ), giving the locomotive 209 kilonewtons tractive effort during starting. For electric dynamic braking, their traction motors ac t as generators with the electricity thus generated being absorb ed in resistors mounted within the locomotive. With a total weight of 98.6 tonnes, and a length of 18 metres, these locomotives are capable of speeds of 121km/hr. 0 b::I 0 if__:=~--~cl ~) I Y C:> v/;LINE w [y [O ~ I - -- - THE VICTORIAN "L" CLASS 1500-volt DC locomotive is propelled by six traction motors, each rated at 298kW. This 98.6-tonne Coco locomotive is used for hauling much of the coal train traffic in the south-eastern corner of Victoria. (Drawing courtesy V-LINE). 80 SILICO N CI-111'