WWW.REFERATCENTRAL.ORG.UA - Я ТУТ НАВЧАЮСЬ

... відкритий, безкоштовний архів рефератів, курсових, дипломних робіт

ГоловнаІноземна мова - Англійська, Німецька та інші → The history of railways - Реферат

The history of railways - Реферат

Railways in wartime

The first war in which railwaysfigured prominently

was the American Civil War (1860-65), in which the Union

(North) was better able to organize andmake use of its railways than the Confederacy (South). The war was marked by а famous incident in which а 4-4-0 locomotive

called the General was hi-jacked by Southern agents.

The outbreak of World War 1 was caused in part by the

fact that the mobilization plans of the various countries, including the use оf railways and rolling stock, was planned to the last detail, except that there were nо provisions for stopping the plans once they had been put into action until the armies were facing each other. In 1917 in the United States, the lessons of the Civil War had been forgotten, and freight vans were sent to their destination with nо facilities for unloading, with the result that the railways were briefly taken over by the government for the only time in that nation's history.

In World War 2, by contrast, the American railways performed magnificently, moving 2,5 times the level of freight in 1944 as in 1938, with minimal increase in equipment, and supplying more than 300,000 employees to the armed forces in various capacities. In combat areas, and in later conflicts such as the Korean war, it proved difficult to disrupt an enemy's rail system effectively; pinpoint bombing was difficult, saturation bombing was expensive and in any case railways were quickly and easily repaired.

State railways

State intervention began in England withpublic demand for safety regulation which resulted in Lord

Seymour's Act in 1840; the previously mentioned Railway

Gauges Act followed in 1846. Ever since, the railways havebeen recognized as one of the most important of nationalresources in each country.

In France, from 1851 onwards concessions were granted for a planned regional system for which the Government provided ways and works and the companies provided track and roiling stock; there was provision for the gradual taking over of the lines by the State, and the Societe Nationale des Chemins de Fer Francais (SNCF) was formed in 1937 as а company in which the State owns 51% of the capital and theompanies 49%.

The Belgian Railways were planned by the State from the outset in 1835. The Prussian State Railways began in 1850; bу the end of the year 54 miles (87 km) were open. Italian and Netherlands railways began in 1839; Italy nationalized her railways in 1905-07 and the Netherlands in the period 1920-38. In Britain the main railways were nationalized from 1 January 1948; the usual European pattern is that the State owns the main lines and minor railways are privately owned or operated by local authorities.

In the United States, between the Civil War and World Wаr 1 the railways, along with all the other important inndustries, experienced phenomenal growth as the country developed. There were rate wars and financial piracy during а period of growth when industrialists were more powerful than the national government, and finally the Interstate Commerce Act was passed in l887 in order to regulate the railways, which had а near monopoly of transport. After World War 2 the railways were allowed to deteriorate, as private car ownership became almost universal and public money was spent on an interstate highway system making motorway haulage profitable, despite the fact that railways are many times as efficient at moving freight and passengers. In the USA, nationalization of railways would probably require an amendment to the Constitution, but since 1971 а government effort has been made to save the nearly defunct passenger service. On 1 May of that year Amtrack was formed by the National Railroad Passenger Corporation to operate а skeleton service of 180 passenger trains nationwide, serving 29 cities designated by the government as those requiring train service. The Amtrack service has been heavily used, but

not adequately funded by Congress, so that bookings,

especially for sleeper-car service, must be made far in

advance.

The locomotive

Few machines in the machine age have inspired so much affection as railway locomotives in their 170 years of operation. Railways were constructed in the sixteenth century, but the wagons were drawn by muscle power until l804. In that year an engine built by Richard Trevithick worked on the Penydarren Tramroad in South Wales. It broke some cast iron tramplates, but it demonstrated that steam could be used for haulage, that steam generation could be stimulated by turning the exhaust steam up the chimney to draw up the fire, and that smooth wheels on smooth rails could transmit motive power.

Steam locomotives

The steam locomotive is а robust and

simple machine. Steam is admitted to а cylinder and by

expanding pushes the piston to the other end; on the return stroke а port opens to clear the cylinder of the now expanded steam. By means of mechanical coupling, the travel of the piston turns the drive wheels of the locomotive.

Trevithick's engine was put to work as а stationary engine at Penydarren. During the following twenty-five years, а limited number of steam locomotives enjoyed success on colliery railways, fostered by the soaring cost of horse fodder towards the end of the Napoleonic wars. The cast iron plateways, which were L-shaped to guide the wagon wheels, were not strong enough to withstand the weight of steam locomotives, and were soon replaced by smooth rails and flanged wheels on the rolling stock.

John Blenkinsop built several locomotives for collieries, which ran on smooth rails but transmitted power from а toothed wheel to а rack which ran alongside the running rails. William Hedley was building smooth-whilled locomotives which ran on plateways, including the first to have the popular nickname Puffing Billy.

In 1814 George Stephenson began building for smooth rails at Killingworth, synthesizing the experience of the earlier designers. Until this time nearly all machines had the cylinders partly immersed in the boiler and usually vertical. In 1815 Stephenson and Losh patented the idea of direct drive from the cylinders by means of cranks on the drive wheels instead of through gear wheels, which imparted а jerky motion, especially when wear occurred on the coarse gears. Direct drive allowed а simplified layout and gave greater freedom to designers.

In 1825 only 18 steam locomotives were doing useful work. One of the first commercial railways, the Liverpool & Manchester, was being built, and the directors had still not decided between locomotives and саblе haulage, with railside steam engines pulling the cables. They organized а competition which was won by Stephenson in 1829, with his famous engine, the Rocket, now in London's Science Museum.

Locomotive boilers had already evolved from а simple

flue to а return-flue type, and then to а tubular design, in which а nest of fire tubes, giving more heating surface, ran from the firebox tube-plate to а similar tube-plate at the smokebox end. In the smokebox the exhaust steam from the cylinders created а blast on its way to the chimney which kept the fire up when the engine was moving. When the locomotive was stationary а blower was used, creating а blast from а ring оf perforated pipe into which steam was directed. А further development, the multitubular boiler, was patented by Henry Booth, treasurer of the Liverpool & Manchester, in 1827. It was incorporated by Stephenson in the Rocket, after much trial and error in making the ferrules of the copper tubes to give water-tight joints in the tube

plates.

After 1830 the steam locomotive assumed its familiar form, with the cylinders level or slightly inclined at the smokebox end and the fireman's stand at the firebox end.

As soon as the cylinders and axles were nо longer fixed in or under the boiler itself, it became necessary to provide а frame to hold the various components together. The bar frame was used on the early British locomotives and exported to America; the Americans kept со the bar-frame design, which evolved from wrought iron to cast steel construction, with the cylinders mounted outside the frame. The bar frame was superseded in Britain by the plate frame, with cylinders inside the frame, spring suspension (coil or laminated) for the frames and axleboxes (lubricated bearings) to hold the

Loading...

 
 

Цікаве