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By BRYAN MAHER PART 1 - THE BIRTH OF STEAM AND ELECTRIC LOCOMOTIVES The early 1800s to the 1920s saw the greatest expansion of transportation and industrialisation the world has ever seen, and it was all based on the steam locomotive. But within another 40 years the steam locomotive would be largely obsolete because of the diesel electric loco and the electric loco. The world changed - for better or for worse - one Lenten Sunday morning in 1803. The place was a 6 SILICON CHIP small Welsh village, the parish church in particular . Young Richard Trevithick had chosen this day to try out his dream. Trethivick was a Cornishman by birth, a South Wales coalmine captain by profession, and an inventor by choice. He had long observed the large stationary steam engines used to pump water from the mines. Trevithick reasoned that if the boiler and the engine were wheel- mounted, might not the pistons and cranks actually turn the vehicle wheels themselves , producing motion? The model To test the idea, Richard Trevithick built a model: four wheels, a boiler with a small fire under it, and two steam cylinders with pistons connected to cranks on the wheels. The next thing needed -,--· In this first article, we examine how the steam loco developed from a curiosity to massive engines weighing 550 tonnes, while in the some period electric locomotion was only just beginning. Richard Trevithick quickly gathered his invention in his arms and ran off. Though none realised it, the world changed then and there: ·no longer would the human race depend on animals for transport. The railway era had begun. Stories spread quickly in Wales and very soon young Richard was offered a wager by workmates. •'Bet you cannot build a full-size machine that can haul our mine coal trucks". For years the mines had used four wheeled trucks, hauled by pit ponies plodding between parallel flanged rails or plateways. The tracks were placed a suitable distance apart so the wheels, two shafts and pulling chains were just clear of a horse's buttocks. In England the Clydesdale horses, being the largest, set the required spacing between rails at about 56.5 inches. Thus, even today, the world "Standard Railway Gauge", the distance between inside edges of the rails, is just that: four feet, eight and one half inches (or 1435mm). with steel rails carried on slabs of timber, steel or concrete "sleeping" in the ground. was a suitable place for a trial run. Roads were wet and muddy but the dry stone paved area in the village church yard was inviting. He lit the fire, raised steam and off it ran in the direction of the church front doors. Success! The first dream of his life achieved! At that moment the church doors were flung open from within, and fresh from a sermon on the evils of the world came the village parishioners. With one look at Richard's steaming, hissing running machine they turned and stampeded back into the church screaming "The Devil himself is after us". The very first loco Within 12 months young Trevithick had built his first steam locomotive at Winfield's Foundry in Gateshead and ran it on the Pen-ydarran mine railway tracks, so winning the bet in 1805. The era of mass travel had begun. 20 years later, on 27th September 1825, another pioneer, George Stephenson, had also realised a lifelong dream, having convinced sufficient moneyed people to share in his new company, the Stockton And Darlington Railway. The world's first Public Railway, was opened with suitable fanfare, ceremony, and (let's say this bit very quietly) some derailments. Many world firsts can be claimed for that year: at Stockton in Durham County the very first railway ticket was sold, the first iron railway bridge was built, the first architect-designed sculptured stonework railway viaduct was constructed and, for the benefit of you and I, the world's first photograph of a working train was taken. This was also the first railway to be established across public land, roads and streets, by authority of an Act of Parliament. Such was the genius of George Stephenson that from his fertile mind came the basic design of the first real steam railway locomotive capable of operating a public railway, running for hours on end hauling freight and passengers, in short - the first working railway system. True, there were other locomotive designers in the field before Stephenson. But Richard Trevithick's 1805 model at Gateshead, the Blenkinsop model of 1812 and William Hedley's 1813 Puffing Billy all used principles that failed on the hard road of experience. Some used a single cylinder, all used gear drive and one used a huge flywheel. George Stephenson's success was based on hard experience gained with his Killingsworth locomotives, which were designed for hauling coal out of mines. Improving on these, he designed his 1825 model christened "Locomotion". Opposite page: the Pennsylvania GGl class made by General Electric were America's first and most long-lived high speed mainline electric locos. These 214 tonne monsters did daily service on the Pennsylvania Railroad for nearly 50 years up until 1981. (Amtrak photo). NOVEMBER 1987 7 / / ' ,.,.~,- ./~:/~ / // ~ NSW loco No 4601 undergoing trials in 1956. One of twenty electric locos built for the Blue Mountains section, these 2.8MW 114 tonne units have given 30 years of excellent service. (NSW SRA photo). Of vital importance were the two double-acting cylinders; ie, power was produced on every piston upstroke and on every down stroke. Rod-coupled to four driving wheels, with cranks on opposite driving wheels set 90 degrees apart, these formed a combination which always produced starting tractive effort (drawbar pull) no matter in what attitude the loco had previously stopped. Contrast this with the typical stationary one-cylinder single-acting steam engines of the day, producing power during less than one half of each revolution, during the piston down-stroke, and requiring a large J=.=~~~~===-.=~~~~~-•f . . /~e.-½ ~,< .-.~- . . l- -r :+~:-J -~t~-' ~ };,,~L"":::li'lo~l:r~l~~ ~~ ~ ?, ·~i.... 0 tt · i.~-:_ -: . u., ~(~ --~::::-- ~~~t~ ~:?~-'-~-~---~~~t~:-~;--.~v~·:~ :·.~:/-~/I;-.-·~·:-:~~~~ 0 1 The world's first electric "Locomotive" designed and built by Robert Davidson in 1842. It weighed 6 tonnes, carried its own batteries and ran at 7km/h. (Original drawing reproduced by courtesy of the British Science Musiem and the Institute of Electrical Engineers London). 8 SILICON CHIP flywheel to drive the load during the remainder of each circle. Furthermore, starting required the flywheel to be pulled by hand to a suitable attitude with the piston halfway down the cylinder. George Stephenson's Locomotion used two extra eccentric cranks on a driving axle to drive two slide type steam valves, called "D" valves, mounted between the wheels. These admitted steam from the boiler to the power cylinders at appropriate timing. The timing could be varied to save steam after the train was accelerated by admitting short bursts which were then allowed to expand within the cylinder. Further timing variation reversed the direction of running. Also at the end of each piston stroke the valves opened a path from the cylinder to exhaust spent steam up the funnel to improve the draft for the fire. These design principles seemed obvious to George Stevenson at the time but not even he could forsee their extensive future. His simple genius was such that these basic ideas would prove essential and perforce become the design foundation of every steam locomotive ever built. Improvements With his ideas now known worldwide, improvements quickly came as other designers entered the field. Within nine years, steam cylinders would be changed to horizontal position to facilitate springing of driving wheels. And, in America, that fabulous loco designer Samuel Baldwin introduced leading bogies to allow higher running speeds on curves. Eventually the number of driving wheels on some locomotives would reach as high as twenty and engine weights would grow from Locomotion's tiny 6 tonnes to as much as 550 tonnes. But only the introduction of superheating and higher boiler pressures caused any real increase in efficiency over Stephensons's original design. It is an amazing fact that George Stephenson's essential design was never changed in all the entire dynamic 130 year saga of the steam loco. Diagram of the motors of Robert Davidson's first Electric Locomotive. A, B, and C are iron bars attracted in turn by switched electromagnets Ml and M2. (Drawing by Anthony F. Anderson reproduced by permission). pulley grooved plate 1upport bars andl• llcl Enter electric traction In the midst of the frenzied advances in steam railways, there were other developments of significance. In Scotland, we find Robert Davidson, a manufacturing chemist of Aberdeen. Born in the year of Richard Trevithick's steam locomotive success, he attended Marischal College at the University to study the Arts, but spent so much time delving into chemistry, electrochemistry and the brand new science of electromagnetics that he never did graduate. Apprenticed to his father in the grocery trade he left this for a freelance career manufacturing yeast, dyes and other chemicals from which he made sufficent money to support experiments with fundamental variable-reluctance type electric motors. The Edinburgh And Glasgow Railway, opened on Feburary 21 , 1842, ran a regular timetable of four steam trains in each direction daily. In the third quarter of that year Robert Davidson persuaded the Railway management to allow The battery design used by Robert Davidson. Two or four of these batteries powered his first loco. The zinc and iron plates were pulled out of the electrolyte to control the speed of the loco. (Drawing by Anthony F. Anderson reproduced by permission). The field magnets of Robert Davidson's traction motors used iron plates as laminations. (Drawing by Anthony F. Anderson reproduced by permission). NOVEMBER 1987 9 This 109 tonne 2.9MW electric loco is the first of a fleet of electric locos to be used in Queensland for hauling coal. It has been designed with triple bogies, to traverse very tight curves, and is powered from a 25kV AC overhead line. him to use their tracks for an experiment of his, in between train schedules of course. He had constructed a full-size rail truck 4.9 metres long, 2.13 metres wide, with wooden cylinders surrounding both axles. On each cylinder he had mounted three long iron bars and a threesegment commutator. Attracting the iron bars were eight electromagnets whose coils were switched by the commutators, direct current being supplied by two banks of oells. There were 80 cells originally, with more added later. These zinc-iron batteries consisted of a wooden trough divided into cells, each containing one zinc plate in between a pair of iron plates, all plates being supported by a wooden lid. Each plate was 300mm x 380mm and the electrolyte for his battery was 1:7 sulphuric acid and water. It appears that he used a pulley system to raise and lower the plates in the electrolyte, and this con10 SILICON CHIP stituted the motor speed controller. With all this massive electrical gear it is not surprising that the complete truck weighed about 6 tonnes. The electromagnetic theory known at the time was not sufficiently complete for Robert Davidson to appreciate the severe eddy current losses incurred by his use of solid iron in rapidly switched magnets, for it was probably this loss more than any other factor that limited the speed achieved by his "Locomotive" to about 7km per hour. Thus the world's first electric railway vehicle capable of carrying people ran at Edinburgh on 22nd September, 1842 over a distance of 2.4 kilometres. Unfortunately, Davidson did not publish his results, nor did he patent his inventions. But his achievements were observed and documented by other scientists and engineers to whom we are indebted for these details of the world's first electric locomotive of any size. Following Michael Faraday's primeval direct current motor and generator principles of 1821 and his homopolar generator of 1831, Negri built the first electromagnetic motor (actually a vibrator) and Pixii constructed the first commutator in 1832. It was mentioned in Michael Faraday's correspondence that Robert Davidson was producing useful electromagnetic motors in 1837 and railway applications were then predicted, although his activities in the earlier part of that decade are unknown. In other countries Thomas Davenport had a model electric railway running at Brandon, Vermont in 1837 and Jacobi in Russia had electric propulsion of a ship working in 1838. One Captain Taylor patented an electric motor in 1840 which appears to be a copy of Davidson's earlier electric railway "Locomotive" and other work exhibited to the public at Aberdeen in 1840. A strange regressive design electric locomotive was built in the USA by one Mr Page in 1851 and run on the Washington & Baltimore Railroad. It copied steam reciprocating mechanics although it was electromagnetically operated. Apparently it was unconvincing. Not surprisingly, the railway owners of the world took little or no notice of these electrical developments for more than · 40 years. They just continued to outdo each other with bigger and faster steam locos. No challenger to those hissing, puffing monsters could be seen coming from any direction, even by the most farsighted prophet. Yet such forecasters would all be wrong, for just out of sight over the temporal horizon two happenings would eventually change the railway scene completely. But that will be our story next month. Grateful thanks to Prof. A.F. Anderson; Prof. C. Davidson; Queensland Railways; NSW SRA; Amtrak, Clyde/ASEA-Walkers; and IEE (Eng) for material and permission to reproduce. ~