MECHANICS AND USEFUL ARTS. 29 



IMPROVED TRACTION UPON STEEL RAILS AND STEEL-HEADED 



RAILS. 



It has been too much the practice of railvva? managers to con- 

 sider only the increased durability of steel. A less striking, but 

 perhaps equally important advantage, is that it has double the 

 strength and more than double the stiffness of iron. Some 3 

 years since, Mr. George Berkley made, in England, above COO 

 tests of the stiffness of steel and iron rails of equal section. The 

 rails were supported on S-leet bearings, and loaded with dtnid 

 pressure at the middle. The first rails tried weighed G8 pounds 

 per yard, and loads respectively of 20 tons and 30 tons were ap- 

 jDlied. The average of 427 tests of the Eubw Vale Co.'s and two 

 other standard makers of iron rails, gave, with 20 tons, a deflection 

 of five-eighths inch and a permanent set of one-half inch. With 

 30 tons tiie deflection was two and one-fifth inch and the perma- 

 nent set two and one-sixteenth inch. With Brown's steel rails, 

 45 tests gave an average deflection of but five-sixteenths inch and 

 permanent set of one-eighth inch. With heavier rails and loads, 

 the comparative stitt'ness of steel was still more marked. The 

 great and constant resistance of traction, and the wear and tear 

 of track wheels and running gear, due to the deflection of rails 

 between the sleepers and the perpetual series of resulting concus- 

 sions, may be much reduced, or practically avoided, by the use 

 of rails of twice the ordinary stifiness ; in such a case, however, 

 reasonably good ballasting and sleepers would be essential. 

 When a whole series of sleepers sinks bodily into the mud, the 

 consideration of deflection between the sleepers is a premature 

 refinement. If the weight of steel rails is decreased in propor- 

 tion to their strength, these advantages of cheaper traction and 

 maintejiance will not, of course, be realized. The best practice, 

 here and abroad, is to use the same weight for steel as had been 

 formerly employed for iron. 



Many attempts have been made in England, on the Continent, 

 and in this country, to produce a good steel-headed rail, and not 

 without success. Puddled steel-heads have all the structural de- 

 fects of wrought iron, as they are not formed from a cast, and 

 hence homogeneous mass, but are made bj'' the wrought-iron pro- 

 cess, and are, in fact, a " high," steely wrought iron. They arc, 

 however, a great improvement upon ordinary iron, although 

 probably little cheaper than cast-steel heads. Rolling a plain cast- 

 steel slab upon an iron pile has not proved successful. The weld 

 cannot be perfected, on so large a scale, and the steel peels olT 

 under the action of car- wheels. Forming the steel slab with 

 grooves, into which the iron would dovetail when the pile was 

 rolled into a rail, has been quite successful. The greater part of 

 some 500 tons of such rails, made in tliis country, and put down 

 where they would be severely tested, about 4 years ago, have 

 outworn some 3 iron rails. Others failed in the iron stem, which 

 was too light, after a shorter service. Rolling small bars of 

 steel into the head of an iron pile has been recently commenced 



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