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PART 3 - TIIE PROBLEM OF BR 'I'H E EVOLUTION OF ELECTRIC RAILWAYS While early railway development in England and America is well documented, much pioneering work was also done in Europe, particularly in Fronce, Germany and Sweden. By BRYAN MAHER Sweden did some impressive development for they were in the railway business quite early, having used horse-drawn mine railways as early as 1798. The first steam locomotive built in Sweden was named the "Forstlingen" and began service on a private line from 4 SILICON CHIP Ore bro to Nora in March 1856. The Government responded with the opening of a line from Goteborg to Jonsered and another from Malmo to Lund, the first segments of their future National Network, in December of the same year. Within six years the railway crossed their country from ,/', Stockholm to Goteborg and by 1892 they had in operation the world's first International Train Ferry, connecting Helsingborg in Sweden with Helsingor in Denmark. In 1885 to 1902 they built the fi~st railway within the ~retie Circle, the Lapland Railway, · · to transport iron ore from Kiruna to Norway's ice-free seaport Narvik. This railway was electrified in 1915. Extended to the Swedish port Lulea on the Gulf of Bothnia in 1903, the whole 490-kilometre length was fully electrified by 1922. This world-first initiative in the development of low frequency alternating current traction H· •·-· At left, a view of Sweden's Lapland Railway in mid-summer. This line runs within the Arctic Circle but ◄ carries 38 trains per day in each direction. (Bryan Maher photo). systems initially used a 15kV 15Hz supply generated specifically for traction in low speed water-driven alternators at the Porjus Power Station and transmitted via 80kV single phase power lines. The motors used are series commutator motors. The reason for the low frequency supply is that on higher frequencies like 50Hz the interpoles do not effectively cancel the armature magnetic field reaction on the main magnetic field, leading to severe arcing between commutators and brushes. The permanent summer snowline in such northern climes is a mere 1000 metres above sea level. Since about half the line's length is above 500 metres elevation, the track is only free of snow during midsummer. Therefore, the electrical designers decided to house all trackside 80kV/15kV transformers within large brick buildings for protection. But this plan came slightly unstuck when the electrical workers had the transformers temporally installed and working out in the open while the bricklayers were still at it. As winter approached, all work necessarily ceased but the transformers and electrical gear performed beautifully all winter, even in blizzard conditions. The cold air gave better cooling and allowed the transformers some overload rating so the engineers decided to leave them where they were. Keeping in mind the low frequency used, transformer cores and hence complete transformers are considerably larger than similar 50Hz types so the now unwanted brick buildings had been built to generous proportions. But what use could be made of them now? Even- tually, these strong brick structures were put to good use as the roomiest passenger waiting rooms on the system. As well as being a lesson in international cooperation, as locomotives of both countries (Sweden and Denmark) share the work, this line is unusual for Europe as ore trains of 5500 tonnes are commonly hauled by Dm class 4.8 megawatt (6400 horsepower) or Dm3 class 7.2 megawatt (9400 horsepower) locomotives. Perhaps you may find it difficult, gentle reader, to picture such an Arctic installation as a busy thoroughfare but in fact the average traffic is 38 trains per day in each direction six passenger and 32 ore trains. More than 30 million tonnes of iron ore are shifted to Narvik annually. When other Swedish lines were electrified, frequency converters were used to derive 16.666Hz single phase traction supply at 15kV from the three phase national grid 50Hz system. This method eventually replaced the 15Hz supply on the Lapland line also. By 1942 the world's longest electric train journey was in Sweden, a distance of 2022 kilometres. Braking In the 1830's it became quite apparent to the railway world that a moving train is very hard to stop and the early increases in locomotive power and train weight only increased the problem. Originally in England, hand operated brakes were fitted to each wagon and a guard was appointed to run along beside the train and set each truck's brakes as the train slowly rolled over the top of a hill. You may find it hard to believe, but this method of braking was still use on a few privately owned coal lines in the Newcastle areas as late as the 1960s. Increases in train speed in the 1840s soon put this method in the "too hard" category. American railroads responded by This two-axle electric locomotive was made by Messrs Fowler & Co, of Leeds, England at the turn of the century. It was intended for use on short lines. Electrical pickup was via trolley wheel. (Norm Marks photo). JANUARY 1988 5 turned a valve to allow some air into the "train line" and all truck brake cylinders let go partially or fully so the brakes were pulled on by the brake-springs. The nice part was that should a train coupling break and the train become parted, the hose couplings automatically uncoupled, allowing air into the lines of both parts of the train and all were brought to a safe stop. This method was used for years in Britain but trouble came when trains became heavier and faster still. Other countries experienced the same problems as they were building lines up and down mountains. There is a limit to the pull that can be exerted by a vacuum cylinder as it can only have one atmosphere pressure or about 15 psi acting on the piston. That limits the useable strength of the brakespring and hence limits the braking force that can be applied. Some way of using higher pressures was clearly needed. Westinghouse air brakes Built in 1901 by Messrs Siemens & Halske, of Berlin, Germany, this experimental loco used 50Hz three-phase AC at 10,000 volts. On board transformers stepped the voltage down to 750VAC. Just imagine the complications of the overhead wiring at points. (Norm Marks photo). fitting a walkway along the top of the roof of every wagon. At the end of each wagon's walkway was a handwheel to apply the brakes. Brakemen had to run the length of the speeding train to apply the brakes by turning each wagon's handwheel. When some handwheels were found hard to turn, each man was supplied with a heavy wooden club to assist. Tales of the Roaring West showed that these brakemen's clubs were useful in a brawl too! With longer trains up to four brakemen per train were employed, two riding in the brakevan and two riding on the engine. If two large locomotives were used doubleheaded, a train crew could be considerable, with a driver and two firemen to each loco , four brakemen and a conductor, eleven men in all. Such a headcount can only reflect the low wages and long working hours of those days. Can you appreciate their tough working 6 SILICON CHIP conditions descending the mountains in a winter snowstorm? To further assist in stopping trains the caboose (guard's van) was made large and heavy and equipped with a powerful handbrake operated by the conductor from within. Coal trains in the Newcastle area up to the 1960s still used the same idea. Vacuum brakes England, with more finesse, invented a vacuum operated brake system with vacuum pipe, hoses and hose couplings running the length of the train. Brakes on each wagon were pulled on by a spring and simultaneously held off by vacuum in a piston and cylinder. The train driver set the steamdriven vacuum pump in operation which evacuated the "train line" (ie, the pipe, hoses and all brake cylinders), pulling all truck and loco brakes off. This was the running condition. To stop his train, a driver simply That's where the Americans came into the picture. Inventive readers across the country can be heard mumbling something like "So what's the problem ? Why not just apply compressed air to the piston, any pressure you like to make it, instead of vacuum? Use 100 psi or 200 psi or whatever is necessary to pull off a more powerful brakespring?" Such an idea would give protection in case of a train coupling breaking. Furthermore, a wagon parked on a siding would perforce have its brakes on, and a handwheel and gearing could be used to pull the brakes off a parked truck when we want to move it for loading. The idea has in fact been used for short trains; you could call it a " straight air" system. But the catch comes with a long train, say a kilometre long with 100 wagons, each with its brake cylinder full of air. That's a large quantity of air to be moved a long distance to the engine before the brakes are applied, and-the brakes would be firmly "on" in the front wagons long before the air had travelled from the back of the train where the brakes are still "off" This would result in a nasty Pictured is a battery-operated loco used on the Lancashire and Yorkshire Railway. The loco weighed 22 tonnes and was capable of pulling loads up to 120 tonnes. (Norm Marks photo). "concertina" effect every time the driver uses his brake control. The Westinghouse organization of the USA patented a system wherein each wagon carries its own high pressure air reservoir and a 3-way air valve called the "triple valve". Brakes are applied by air pressure, not by spring, when the triple valve opens a path from the wagon's air reservoir to the brake cylinder. Brakes are released when the triple valve opens a path from the brake cylinder to atmosphere, letting the air escape, and simultaneously closing off the wagon ' s air reservoir. The lost air from the wagon's reservoir must be replaced for the next brake application. While brakes are not being used the triple valve opens a path from the train air pipe to the wagon's air reser- voir, allowing the air compressor on the locomotive to refill all wagon air reservoirs. This pumping-up process usually takes some time but that is acceptable if the system is used intelligently. "And just how?" you ask "does that clever triple valve know when it is supposed to change its function as aforesaid?" Yes it is a clever little valve indeed. Its function is dictated by the difference in the pressure between the wagon's reservoir and the "train line". So the loco driver controls the triple valves and thereby the brakes by letting air out of the train line or allowing his compressor to pump the line back up again. The above story is a simplified explanation but it does show that full brakes can be applied by emptying to atmosphere only the air contained in the train line pipe. This is not a great quantity of air so it can be done fairly quickly. And if coupling breaks the train, full brakes are automatically applied to all train sections. Furthermore the guard or conductor can apply emergency brakes to the whole train, including the locomotive, by opening a simple onoff valve mounted in his guard's van or caboose emptying the air out continued on page 74 Now being phased out, this is typical of the heavy caboose or guards' van used on American railroads. (Conrail-J. Hill photo). JA NUARY 1988 7 connected. To the left of these is a shielded phono jack to which the coaxial line feeding the receiver is connected. If you have trouble finding a two-pole, four position rotary switch, a two-pole, six-position switch may be substituted. The three-wire Flexo Another Flexo aerial uses three antenna wires and a three-conductor transmission line as shown in Fig.2. In that arrangement, the three antenna wires are spaced 120 degrees in the horizontal plane. It, too, is erected in the inverted-V fashion. The ends are dropped down to three metal fence posts near ground level. A view of that configuration is shown in one of the photos. The three transmission line wires run down the outside of the PVC mast through screw eyes to three terminals that are mounted in the PVC piping at chest level. From there, a three-wire transmission line enters the radio room and connects to the Flexo switcher. When there are three wires that are part of the transmission line, there are as many as twelve individual combinations that can be switched in. However, the six combinations provided by the arrangement shown in Fig.2 give good results, and little improvement can be obtained with additional combinations. The switching arrangement shown can select any individual wire for use as a long-wire antenna. The remaining three positions use the antenna wires in three separate dipole configurations. As a result, the Flexo has some limited directivity when operating as a switched dipole configuration on the lower-frequency bands. On the higher-frequency bands, the single-wire combinations also display directivity. However, the main advantage is that it gives you six combinations to choose from in obtaining the best reception possible for difficult propagation and interference conditions. Don't expect it to be a cure-all; some additional ·• The switch box is simply an inexpensive metal cabinet that carries the selector switch, two screw terminals and a phono jack. options may be necessary under difficult conditions. The switch is a two-pole, six-position type as recommended previously. Note that Sla selects one of the individual antenna wires when in positions 1, 2 and 3. Those same positions on Slb are left unconnected. Thus, you are operating with a singlewire feed for the first three positions and true coaxial feed for the latter three positions. The last three positions (4, 5 and 6) of switch Slb connect the wires in pairs to give a dipole configuration. In the 4, 5 and 6 positions, an appropriate antenna wire is connected to the braid of the small section of coaxial line that connects the output of the switcher to the receiver. In checking out your results, it may be advantageous to wire the switcher in terms of the physical positioning of each antenna wire. In wiring the Flexo switch, be certain to mount three insulated terminals on the box for connecting the wires from the antenna. You can use the same size box as for the previous antenna. ~ Evolution of Electric Railways: ctd from p.7 of the train line pipe, commonly known as "pulling the train's tail". By 1950 the railway world was changing fast. Diesel electric locomotives had been increasing in numbers since the war years and superseding many steam locos. The first advantages claimed for the diesels were quicker starting and longer times between overhauls. As for running cost measured in dollars per ton-mile of train hauled, on some American railroads the diesel electric could do no better than existing steam locomotives. In many countries , including Australia, running costs of old worn-out steam plant serviced in ancient loco sheds did exceed the expense of servicing and refuelling 74 SILICON CHIP new diesel electric machines in brand-spanking new service shops. A few United States railroads did show clearly that a large ·modern steam locomotive could be serviced and refuelled in a well-equipped running shop at a cost less than or equal to the equivalent expense for diesel electric units of the same power. The Norfolk & Western Railway was one such line which built its last steamer in 1953 and continued to use steam locomotives economically right up to April 4th, 1960. Even then, economy was not the reason for the death of steam. The problem was that they were just about the only railroad left using steam and new parts and plant became virtually unobtainable. It is interesting that the major manufacturers Alco, Baldwin and Lima in America built their last steam locomotive in 1947, 1949 and 1949 respectively, while in Australia the last steam locomotive to enter service, in January 1957, was a 269 tonne giant, the articulated Garratt built by Beyer, Peacock & Co Ltd, of Manchester England. So ended the amazing 160 year steam era, with the diesel-electric locomotive now ruling the world's lines. But let us not forget the other contender, the electric locomotive which is widely used around the world, expecially in Europe. Next month when we will delve into Australia ' s part in this fascinating saga. ~