ON AMKUICAN rRRMANKNT WAY. 



595 





Vr. and Vrr., as adopted nnd in nso on a iimnbcr of Amoriunn roads Those 

 will reprcsoiifc pretty fairly tlio general practice throuj^hoiU the cointry. 

 In (comparing tlicHe it must be borne in juind that the xcrviee on some 

 lines is not so severe as on others; also that the same railroad eoinpany 

 uses lighter fiections on its branch lini^s than on its main stem, on account 

 of the diilercnco in service. Sections that are ([uito suitable in one easo 

 nro not so in others. 



The numbers by which the several sections are designated aro those 

 of the (.'ambria Iron Company. Where the roads using any section aro 

 noted, and the date is given, it simply means that this secition was rolled 

 for that railroad at that date. It does not follow that the railroad in 

 <|UCstion may not have ('hammed its section at some other Juill since then ; 

 but this is a matter that conld not bo ascertained, and its {)robal)ility is 

 not very gniat. 



The (I rand Trunk Kail way of Canada uses tho Sandberg pattern of 

 T rail, weight G-') pounds per yard. 



The Chicago and North- \Vestcrn Kailway Company arc using ;>0-feofc 

 vails, tho weight on main lines since 1<"^S2 being ('>'> pounds per yard, on 

 less important lines tiU pounds per yanl, and .some o<» and •">() pound rails 

 on branches. 



Tho material of which rails arc formed rccpiires groat care in selection. 

 It must be suUiciently strong to sustain as a girder, tough to avoid all 

 brittleness and danger of breaking under sudden shocks, and at the samo 

 time compact in texture and having liardnes.i in tho to[) to resist wearing 

 action under service. With iron rails it is sought to arrange for these 

 <(ualities in the packing or building up of tho masses of iron from which 

 tho rails are rolled, taking advantage of tho well-known principle that tho 

 diflTerent parts of tho mass keep their .same relative positions in the section 

 of tho bar when rolled out as in the original pile. Harder material is put 

 in tho top of tho ])ile, and softer in the bottom. Steel r.ails, however, aro 

 rolled from solid ingots, and as a consecjuonco they are of a homogeneous 

 texture throughout. They do not split like iron rails, which sometimes 

 shows the result of imperfect welding between the separate pieces of which 

 the original pile from which the rail was rolled was formed. 



JIails aro rolled to a certain maxiinnm length, oO feet being tho usual 

 standard on American roads ; but there is always a certain proportion of 

 shorter rails allowed, which however must conform to regular specified 

 lengths, these being generally arranged to conform to tho standard 

 spaeings of tho cross-ties. 



The following specification of the Pennsylvania Railroad Company 

 for steel rails, adopted .lannary 27, 1870, may be regarded as a standard 

 for iirst-class manufacture : — 



' As it is tho desire of the Pennsylvania Railroad Company to have on 

 tho roads under their control none but first-class tracks in ovei-y respect, 

 and as the rails laid down on these tracks form an important; part in tho 

 ;ichievement of this result, tho Pennsylvania Railroad Company have 

 found it necessary to make certain demands in regard to the manufacture 

 of their stool rails, with which tho different rolling mills and rail inspectors 

 will be required to comply : — 



' 1. Tho steel used for rails shall be in accordance with the 

 " pneumatic " or " the open hearth " process, and contain not less than 

 thirty nor more than fifty ono-hundredths of one per cent, of carbon. 



' 2. The result of tlie carbon test of each charge, of which the 



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