1. Trang chủ
  2. » Kỹ Thuật - Công Nghệ

An Encyclopedia of the History of Technology part 62 docx

10 413 0

Đang tải... (xem toàn văn)

THÔNG TIN TÀI LIỆU

Thông tin cơ bản

Định dạng
Số trang 10
Dung lượng 161,92 KB

Nội dung

PART THREE: TRANSPORT 592 suburban lines of British main line companies in the London, and Liverpool areas. The first section of the Paris Metro had been opened in 1900, the first New York subway line in 1904. The Metropolitan and District underground railways in London had been electrified between 1901 and 1905, and several more deep level tube railways had been made beneath London. Signalling When the District Railway was electrified it was equipped with automatic signalling of a type already in use in the USA: track circuits actuated electropneumatically operated signals. Those in the open were semaphores; in the tunnels, coloured spectacle glasses moved in front of gas lamps. The Metropolitan then used a similar system, but lit the tunnel signals electrically. From these the modern colour light signal evolved. In 1905 the District Railway became the first to install an illuminated track diagram in a signal box. In 1906 the Great Western Railway started to install automatic train control, using a system in which a ramp between the rails made contact with a shoe beneath the locomotive to apply brakes when it approached a signal at danger. Ancillary buildings Railway buildings at this period—passenger and goods stations, signal boxes, locomotive and carriage sheds, engineering works and administrative offices — Figure 11.3: First electrification in Australia was a section of Victoria Railways’ 5ft 3in gauge Melbourne suburban lines electrified at 1500 volts DC in 1919. Australian Information Service. RAIL 593 ranged, in enormous quantity, from the minuscule to the magnificent and reflected the architectural tastes and techniques of their time. Civil engineering works such as the Forth Bridge, or the Victoria Falls bridge across the Zambesi River, ranked among the greatest then built, and likewise reflected available methods and materials. Reinforced concrete was coming into use for railway structures, and also as a replacement for wood as sleeper material. THE AFTERMATH OF WAR The First World War greatly encouraged the use of the internal combustion engine. In a largely static war, armies of both sides were supplied by temporary railways of 60cm gauge, worked by both steam and internal combustion locomotives: the British army alone took delivery of over 1200 small petrol and petrol-electric locomotives. It was the first large-scale use of internal combustion rail vehicles. However the main railway systems in Europe, where not actually damaged in the fighting, were much over worked, and suffered from lack of maintenance. The war did far more to encourage the development and use of motor road vehicles, and of aircraft, than it did of railways. Afterwards, in the 1920s, the motor bus, the motor car and the motor lorry became serious competitors for rail traffic (see Chapter 8), as in the 1930s did the aeroplane (see Chapter 12). Simultaneously, railways were hard-hit by industrial depression. In Europe and North America, there was an increasing tendency for those railways unable to meet competition to be closed. Slow-speed narrow gauge lines were particularly hard hit. In France, during the 1920s, plans for expansion of rural light railway Britain railway routes reached a peak of 32,893km (20,443 miles) in 1927, and Britain railway routes reached a peak of 32,893km (20,443 miles) in 1927, and then started to decline as the extent of lines closed exceeded that of new lines opened. In the USA routes had already passed a peak of 408,745km (254,037 miles) in 1916. Railways were no longer the automatic choice for transport over distances greater than a few miles, nor were they any longer at the forefront of technological progress. They could, however, fight back, although since railway undertakings are large and cumbersome organizations they appear to have a built-in resistance to change, and it was sometimes long after circumstances had altered for the worse that a reaction eventually appeared. What was needed was to improve and accelerate services, and provide them more economically; to do this, traditional techniques, such as steam locomotion, were improved, and new technologies were adopted, particularly for motive power and signalling. During the 1920s and 1930s colour light signalling was coming into use on main lines in both Britain and the USA, and, in signal boxes, route setting panels were first adopted: thumb switches set up a route on an illuminated PART THREE: TRANSPORT 594 diagram, interlocking being done electrically. Centralized traffic control developed in the USA, enabling train despatchers directly to set points and signals many miles away instead of telegraphing train orders. Electrification of railways continued, notably on the Gotthard line (the original Swiss north-south line over the Alps) in 1921, on the Pennsylvania Railroad between New York and Washington in 1935, and on the Southern Railway—one of the four big companies into which most British railways had been grouped in 1923—where London suburban electrification was extended to the main lines to Brighton, Hastings via Eastbourne, and Portsmouth in the 1930s. Direct current was supplied at 660 volts (later increased to 750 volts) by a conductor rail, a system originally chosen for compatibility with London underground lines with which the suburban lines were linked. Southern electrification was primarily for passenger trains and electric haulage was initially little used for freight. INTERNAL COMBUSTION In the USA petrol-electric railcars at first proved insufficiently robust to be reliable in the hands of men accustomed only to steam. But in 1923 the ElectroMotive Company completed its first such vehicle. This company had been set up by Hal Hamilton, locomotive fireman turned road vehicle salesman, to develop a robust, reliable, petrol-electric railcar which would be built under contract using bought-in components. He was successful: over the next seven years his company produced some 500 railcars, steadily improving designs and establishing a reputation for good service. Its successor would in due course be instrumental in seeing the diesel engine adopted for railway locomotives. In the introduction of internal combustion to railways, Hal Hamilton occupies a position similar to that of George Stephenson in relation to steam power: he did not invent it, but he more than anyone else made it work and got it adopted. The most important and far reaching of the new technologies was that of the diesel engine, with its much greater thermal efficiency than the steam engine; the problem, initially, was to exploit so inflexible a power unit as railway motive power. Mechanical transmission proved practicable only for the lowest powers; for units powerful enough to be of real value hydraulic or electric transmission had to be adopted. One of the earliest enthusiasts for diesel traction was Lenin, at whose instigation funds were allocated in 1922 for development of diesel locomotives. Two were built in Germany, one with electric transmission and the other mechanical, for the Soviet railways. Both appear to have run successfully. In 1923 the Canadian National put into service some diesel-electric railcars with engines made by William Beardmore & Co. in Scotland. In the same year the first American diesel-electric locomotive was built by American Locomotive Co. using a 223.7kW (300hp) Ingersoll-Rand engine and General Electric electrical RAIL 595 equipment. This had the wheel arrangement B-B, indicating two bogies, each with four wheels coupled by rods. With the electric and diesel locomotive came a new style of notation for wheel arrangements: ‘A’ for one powered axle, ‘B’ for two with their wheels coupled by rods, ‘C’ for three likewise and so on. Addition of ‘0’ indicates a group of individually powered axles, i.e. ‘Bo’, ‘Co’, and numbers such as ‘1’, ‘2’, ‘3’ indicate unpowered axles. Descriptions such as 1-D-1 and Co-Co became typical. The notation derived from a system used in continental Europe to describe steam locomotive wheel arrangements. The 1923 American diesel-electric locomotive was intended as a shunting locomotive and as such, on trial, shunted the yards of several US railways. It quickly demonstrated qualities of the sort that were to characterize diesel locomotives vis-à-vis steam: it could work almost round the clock without delays for lighting up or ash-disposal, it was easy to drive and economical to run, but it cost twice as much as a steam locomotive. For the last reason, and because diesel engines were still heavy and slow-running, American railways did not immediately take to diesel shunting locomotives, but the building consortium sold two in 1925, two more in 1926 and from then on their numbers gradually increased. In England in 1932–3 the London Midland & Scottish Railway fitted the frames from a 0–6–0 tank locomotive with a 298kW (400hp) diesel engine driving the wheels by hydraulic transmission. This was part of an attempt to reduce the costs of shunting and it was successful, for from that time onwards the LMS built or purchased diesel shunting locomotives, usually with electric transmission, in increasing quantities. These had not, however, been the LMS’s first essay with diesel traction, for in 1928 it had rebuilt a four-coach suburban electric train as a diesel electric, using 373kW (500hp) Beardmore engine. The first diesel railcar to go into regular, rather than experimental, service in the British Isles was a 3ft (91.5cm) gauge diesel mechanical railcar built for the County Donegal Railways in 1931; the line already had several years’ experience of petrol-engined railcars. In 1934 the Great Western Railway initiated diesel railcar workings for both main and branch line services, using railcars built by AEC Ltd, with engines and transmissions similar to those used in London buses. Power from twin six- cylinder engines mounted on opposite sides of the underframe was transmitted through fluid couplings and epicyclic gearboxes. Diesel railcars were also coming rapidly into use in France at this period: when the Société Nationale des Chemins de Fer Français (SNCF) was formed in 1938, following nationalization of the main line companies, it owned some 650 railcars. The most striking application of diesel power in the early 1930s, however, was in Germany. By 1933 a two-car articulated diesel-electric train, the Flying Hamburger, was averaging 124kph (77mph) for the 286km (178 miles) between Berlin and Hamburg, the fastest regular train service in the world. Three-car sets were later introduced, some of them with hydraulic transmission. PART THREE: TRANSPORT 596 Meanwhile in the USA in 1929 the motorcar manufacturers General Motors Corporation purchased an internal combustion engine maker, the Winton Engine Co., and followed this in 1930 by acquiring Winton’s chief customer: the Electro- Motive Corporation, which then became a division of General Motors. A lightweight 447.5kW (600hp) diesel engine was successfully developed by General Motors; with electric transmission, this was used to power a three-coach streamlined high- speed train built by the Edward G.Budd Company for the Chicago Burlington & Quincy Railroad. Budd used newly-developed techniques to weld the stainless steel from which the lightweight coaches were built. This train was the outstandingly successful Pioneer Zephyr, completed in 1934. It demonstrated its potential soon after completion by running the 1633km (1015 miles) from Denver to Chicago non-stop at an average speed of nearly 125.5kph (78mph), and ushered in an era of high-speed light-weight diesel trains in the USA. Furthermore, in 1935–6 General Motors fitted diesel engines into a few locomotives built under contract; then in 1937 it set up its own manufacturing plant for diesel electric locomotives. The first were 1800hp A1A-A1A locomotives for passenger trains. For the first time the driver’s cab was set back behind a projecting nose, to give protection in case of accident on ungated level crossings. A version lacking a driver’s cab, called a ‘booster unit’, was available for multiple operation when greater power was needed. By 1937 it was already possible to travel from coast to coast in diesel-powered trains. In 1939, General Motors introduced a freight locomotive in which four units produced a total of 4027kW (5400hp), and in 1941 the first ‘road switcher’, or enlarged shunting locomotive able also to haul local passenger and freight trains. LATE STEAM The threat of competition from other forms of motive power and other forms of transport spurred steam locomotive engineers to develop steam traction to its peak. In 1935 the London & North Eastern Railway put on a streamlined steam train, the Silver Jubilee between London and Newcastle upon Tyne (Figure 11.4). Chief mechanical engineer Nigel Gresely had considered high- speed diesel units such as were running in Germany, and rejected them in favour of steam, for he had built his first Pacific in 1922 and developed the type steadily since. For the Silver Jubilee he produced the streamlined version, called A4 class, and it was one of this class, no. 4468 Mallard, which in 1938 achieved the speed record for steam of 202.7kph (126mph) which remains unbroken. In 1937 the LNER and the LMS had put on streamlined expresses between London and Edinburgh, and London and Glasgow, respectively; but the outbreak of war in 1939 halted further development. In the USA streamlining was first applied to a steam locomotive in 1934: to a 4–6–4 of the New York Central Railroad. Streamlining of trains at this RAIL 597 period really had as much to do with increasing the glamour of the train as with reducing its wind resistance: certainly it was effective in doing the former, and many other railways introduced luxury streamlined steam trains. Notable were the Chicago, Milwaukee, St Paul & Pacific—its Hiawatha trains hauled by streamlined 4–4–2s designed for maximum speeds of 193kph (120mph) ran in direct competition with Burlington Zephyrs—and the Southern Pacific: its 4–8–4 hauled Daylight trains between Los Angeles and San Francisco, multi-coloured with bands of orange, red, black and silver along their entire length, were arguably the most glamorous, the most spectacular, of all. Streamlining was the outward aspect of locomotives of advanced design. Many improvements were made in locomotive design at this period—for example, in the USA bar frames and separate cylinders developed into cast steel engine beds, and lightweight alloy steel connecting and coupling rods reduced hammer-blow damage to track. For freight, locomotives of Mallet type, but with simple expansion, were built in increasingly large sizes, the largest eventually being the Union Pacific’s ‘Big Boy’ 4–8–8–4s of 1941 which could haul trains weighing more than 5000 tonnes on lines where the ruling gradient was 1 in 122. In France, André Chapelon studied, re-designed and enlarged locomotive steam and exhaust passages, and markedly improved performance. One of his earliest successes was the Kylchap double blastpipe, Figure 11.4: The London & North Eastern Railway’s answer to road and air competition was the Silver Jubilee streamlined express introduced between Newcastle upon Tyne and London in 1935. National Railway Museum. PART THREE: TRANSPORT 598 designed in conjunction with a Finnish engineer named Kylala: the first of the A4S to be fitted with this device was Mallard. DIESEL TAKE-OVER IN THE UNITED STATES By the time the USA entered the Second World War in 1941, many American railways had some diesel locomotives in service. The builders of steam locomotives, who were starting to produce diesel units, were restricted by wartime regulations to building diesel locomotives only for shunting—but General Motors was allowed to build them for freight train haulage in limited quantities. Wartime conditions meant that all locomotives, steam and diesel, were used to the maximum, and confirmed that diesels could haul greater loads faster and more economically than equivalent steam locomotives. After the war, the Budd Co. introduced diesel railcars using General Motors engines driving through torque convertors. General Motors was able to keep the prices of its diesel locomotives down by offering a standard range built by mass production, and diesel power then took over from steam with quite remarkable speed, so that by 1960 there were very few steam locomotives left at work. The diesel locomotive in the USA eclipsed the highly developed steam locomotive as rapidly and effectively as the steam railway in England, a century before, had eclipsed the highly developed coach services on the roads. Even electrified lines in the USA were not immune, and where they represented interruptions in long diesel runs they were converted to diesel too. After the war luxury passenger trains were revived, but only briefly, for American passenger trains, whether diesel or not, were soon subject to intense and increasing competition from widespread private car ownership on the one hand and internal airline services on the other. Eventually, the likelihood of apparent total collapse of long-distance railway passenger traffic was only prevented by the establishment of Amtrak, the state-supported National Railroad Passenger Corporation, in 1970. This operates a limited but nationwide network of long-distance passenger trains (475 stations served by 38,400km (23,860 miles) of routes in 1985), for the most part over the tracks of railway companies which continue to operate their own freight services. Most of the 735km (346 mile) North East Corridor route (Boston-New York- Washington) has however been owned by Amtrak itself since 1976, and is electrified at 12.5kV AC 25 Hz: electrification has been on the increase again. POST-WAR EUROPE The situation in Europe after the Second World War was different. For one thing, there was no indigenous source of oil. For another, many continental RAIL 599 railway systems came out of the war badly damaged and needed effectively to be rebuilt. Electricity became the preferred source of power, with diesel power used on routes where limited traffic did not justify electrification, or as a temporary expedient pending electrification. The railway systems of France and the Netherlands, for instance, had to be largely rebuilt after the war and the opportunity was taken to electrify substantial mileages. On the Continent, prosperity leading to widespread private car ownership came later than in the USA, and by then the railways were better placed to meet it. Nor are distances between cities so great, so air transport was less of a threat, and was furthermore counteracted by the establishment of the Trans-Europ Express network in 1957. This was set up jointly by the state railways of Belgium, France, West Germany, the Netherlands, Italy, Luxembourg and Switzerland to operate fast daytime diesel and electric expresses between the principal cities of those countries. Austria, Denmark and Spain were later added. Through running was made possible between lines electrified on different systems, by construction of electric trains able to operate from as many as four different types of supply, and on to the Spanish broad gauge system by adjusting wheelsets at the frontier. Thirty years later, the system had evolved into the Eurocity Network set up in 1987, with 64 express train services linking 200 cities in 13 countries. BRITISH RAILWAYS The railways of Britain, after the Second World War, had the worst of both worlds. They were neither so badly damaged as to need total reconstruction, like some continental systems, nor were they relatively unscathed, like those of the USA. They were badly run down and had to struggle along as best they could during a period of post-war austerity. The position was exacerbated by the period of re-organization which followed nationalization of the four large companies, and most of the surviving small ones, into British Railways in 1948. BR did start to install an automatic warning system (as automatic train control was re-named) throughout main lines, using magnetic induction instead of physical contact between ramps and locomotives, and it developed a standard coach with a steel-framed body. But despite work done by the old companies to develop diesel power, a range of standard steam locomotives (low-cost and, by steam standards, easily maintained) was introduced in 1950–1. In 1954, British Railways did put its first diesel multiple unit trains into service. Eventually in 1955 a comprehensive modernization plan envisaged electrifying some lines and introducing diesel locomotives and railcars on others, but by the time it could start to take effect at the end of the decade it was already almost too late: increasing prosperity had made car ownership widespread, and air services were well established. The 1963 report, The Reshaping of British Railways, prepared under the chairmanship of Dr PART THREE: TRANSPORT 600 R.Beeching, proposed that railways should be used for transport where ‘they offer the best available means, and…should cease to do things for which they are ill suited’. The consequence was frenzied modernization of equipment, accompanied by drastic closures of branch lines, secondary main lines, and wayside stations on lines which were retained. One effect was that steam locomotives ceased to be used in normal service in 1968. Comparable dates for some other countries are: the Netherlands, 1958; Irish Republic, 1964; France and Japan, 1975. The comparatively late date for France indicates, rather than any tendency to be old-fashioned, that the changeover from steam to electric and diesel started earlier and was carried out in a more ordered manner. As early as 1954 a French electric locomotive had achieved a world speed record of 330kph (205 mph). The late start made in Britain with large-scale electrification did at least mean that advantage could be taken of the latest technology. Many countries had standardized their electrification systems between the wars—Switzerland, for instance, on 15,000 volts single-phase AC at 16 2/3 cycles, France and Holland on 1500 volts DC. Britain, too, had chosen the latter, but little electrification had been carried out to it. Meanwhile, following earlier trial schemes in Hungary and Germany, the SNCF had electrified a 79km (49 miles) section between Aix-les-Bains and La-Roche-sur-Furon at 20,000 volts single-phase, 50 cycles AC. The voltage was later increased to 25,000. It was confirmed that although locomotives for this system were more expensive than for the DC system, the cost of the overhead and sub-stations was very much less. The system was then used in northern France, and adopted for Britain in 1956, in time to be used on most lines electrified subsequently other than those extending the third-rail system in the south of England. The line from London Euston to Birmingham, Liverpool, Manchester and Glasgow was electrified throughout at 25kV by 1974. In 1958, British Railways had decided to install long-welded rails on main lines throughout the system. The earliest main line diesel locomotives provided under the modernization plan tended to be underpowered, multiple operation on the American pattern being generally impracticable in Britain because of cramped track layouts. The position was ameliorated by introduction in 1961 of Deltic Co-Co diesel- electrics of 2460kW (3300hp) which powered the principal London-Edinburgh expresses for the next twenty years, and more so by general introduction of 2050kW (2750hp) locomotives from 1962. Speeds of 160kph (100mph) were common by the early 1970s; in 1976 the first High Speed Trains went into service. With a pair of power cars each containing a 1678kW (2250hp) diesel engine driving an alternator to feed four traction motors, these trains were designed to reach 200kph (125mph) in regular service; in 1986 one reached 238kph (148mph) on test between Darlington and York. With techniques such as these, British Rail has been able to contain the challenge of road and air for passenger travel. Experience with freight has been RAIL 601 less happy. Probably too much traffic had already been lost to the roads by the early 1960s. At that time many trains were still made up of four-wheeled short- wheelbase wagons, loose coupled and without continuous brakes, which were worked from marshalling yard to marshalling yard. It was calculated that the average transit time was 1 1/2–2 days for an average journey length of 108km (67 miles); nor was the arrival time predictable. Measures to improve the situation have included the introduction of many block trains to carry commodities such as coal, oil and stone in bulk, freightliner trains to carry intermodal freight containers to scheduled services, and the TOPS (Total Operations Processing System) computerized system of freight information and transit control which came into operation in 1975 to monitor continuously the movement of goods rolling stock and locomotives. This and construction of high-capacity air-braked long-wheelbase wagons able to run at speeds up to 120kph (75mph), and so to offer same-day or overnight transits throughout the country, has enabled wagonload traffic to make something of a comeback. FREIGHT CONTAINERS AND BULK FREIGHT Freight containers are older than steam railways—containers were used, for example, on the Derby Canal tramroad to transfer coal between plateway wagon and canal boat and, probably, road vehicle. Containers interchangeable between rail and road were in use in the 1920s in both Europe and the USA, and were well established in the 1950s on British and Irish railways. Recent emphasis on containers, however, has come from international agreements, reached in the late 1960s, for standard dimensions, strength and lifting fittings of stackable containers to be carried by ship, rail and road. As such they have come into widespread use, one notable example being carriage of goods from Japan to western Europe via the Trans-Siberian Railway. An alternative, in countries where both the rail gauge and the loading gauge of railways are large enough, has been carriage of road vehicle trailers by rail. Such Piggyback services carry trailers over the long-haul portions of their journeys in North America, western Europe, and Australia. Operation in Australia has been aided by extension of the standard gauge rail system: the Trans-Australian railway (now operated by Australian National Railways) has been linked with the New South Wales system, and the standard gauge extended, by building new lines or dual-gauging old ones, to Melbourne, Perth and Alice Springs. The completion of standard gauge throughout between Sydney and Perth (over a route where formerly there were three breaks of gauge) was followed by the successful introduction, as late as 1970, of the Indian-Pacific luxury passenger train covering the 3960km (2461 mile) route in about 66 hours. Nevertheless the most remarkable railway operation in Australia is that of the isolated Hammersley Iron Ore Railway in the northern part of Western . lack of maintenance. The war did far more to encourage the development and use of motor road vehicles, and of aircraft, than it did of railways. Afterwards, in the 1920s, the motor bus, the motor. electrification. The railway systems of France and the Netherlands, for instance, had to be largely rebuilt after the war and the opportunity was taken to electrify substantial mileages. On the Continent, prosperity. other countries are: the Netherlands, 1958; Irish Republic, 1964; France and Japan, 1975. The comparatively late date for France indicates, rather than any tendency to be old-fashioned, that the

Ngày đăng: 04/07/2014, 01:20

TỪ KHÓA LIÊN QUAN