RAILS AND STRUCTURAL SHAPES, Manufacture'•of. One of the most important branches of the iron and steel industry is the manufacture of rails. Up to about 1855, all rails were made of wrought iron. In England beginning about 1767, various forms of cast-iron and wrought-iron rails were employed, the first being a grooved rail for tramway purposes, Which was subsequently developed into the regu lar railway by the use of cast-Iron flanged rails: The first wrought-iron rail was patented in England by Biticenshaw, in 1820, and. on ac count of its peculiar form was known as the ((fish-belly* rail. It was the first to be rolled in continuous lengths. embracing several spans and was laid in cast-iron chairs spiked to stone blocks set at intervals of three feet. It weighed about per linear yard. Its manufac ture by the rolling process, however, was quite difficult, and it was superseded by the *fiat-fooe rail which combined a solid head With a flanged base and was laid by being fastened to timber sleepers or tits by spikes driven through the holes in the flange The flat-foot rail was fol lowed by the bridge-rail, the double-headed rail and the builtheaded rail. The kW named, al though involving a great waste of metal, owing to the excessive thickness of the web, is used exclusively in England, while in the United States and almost all foreign countries the rail of the flanged T-section is universally em ployed. It was invented by Col. R. L Stevens, an 1830, but the form in use in America is a modification suggested by the special committee appointed by the American Society of Civil Engineers, in 1893; while the form used in Europe is that invented by Sandberg. It is usually made in lengths of 30 feet, but rails as long as 60 feet are used to some extent. In weight 'it varies •from 25 to 100 pounds per linear yard, according to the amount of traffic, the speed of transportation and the gradients and curves of the roads upon which it is used.
About 1865, a few years following the discov ery of the method of manufacturing Bessemer steel, rails of that material were experimentally rolled in the United States and soon began to supplant those of wrought iron. At the present
time all rails are made. of steel,• and they have probably, contributed more toward the rti' development of this country than any o single product of the steel Industry. The raw materials consist of iron-ore, coke and lime Stone, mixed proportion as follows— ore two pounds, cake one pound and limestone one and one-third 'pound. Two fundamental. esses of manufacture are employed.— the reduc tion of the ore in • the blast furnates and the conversion of the molten metal Into •steel in the converter, followed by the operations of the rolling mill. (See LYON AND STEEL INDUS TRY IN THE UNTIED STATES). The Bessemer process of conversion is wetter:My env. ployed on account of its rapidity as com pared with the open-hearth process, taken in Connection with its capability to produce a grade of metal of a quality sufficiently high to satisfy the general specifications for rails. In the manufacture of steel rails, the work of smelting the iron in the blast furnaces is continued day and night, year in and year out, without inter mission, but the converters and the rolling mills are generally shut down from 1.30 P.M., Satur days, to S P.M., Sundays. During the intervening times, the product of the blast furnaces, instead of being poured into the mixers (by which the casts obtained from the different blast fur naces at varying temperatures and qualities are :educed to a common temperature and quality), are run into the pig-casting machine which consists of a seeies of parallel endless- chains of molds arranged to pass in front of the pour ing mouth of the ladle. The molds receive the metal at the lower end of the chain and de liver the casts at the upper end of the chain, where they are loaded upon railway• cars for shipment.