. Railway mechanical engineer . vely small diameterof the wheels, a firebox of sufficient depth can be placedabove the rear drivers without raising the boiler center to anexcessive height. In the new Consolidations, the boilercenter is placed 9 ft. Tyi in. above the rail. In the following table will be found a comparison of theprincipal dimensions and ratios of the Consolidation andMikado types. It will be seen that the new locomotives havesmaller driving wheels and lower boiler pressure than theMikados, but the cylinders are one inch larger in diameterand they have a starting tractive effort
. Railway mechanical engineer . vely small diameterof the wheels, a firebox of sufficient depth can be placedabove the rear drivers without raising the boiler center to anexcessive height. In the new Consolidations, the boilercenter is placed 9 ft. Tyi in. above the rail. In the following table will be found a comparison of theprincipal dimensions and ratios of the Consolidation andMikado types. It will be seen that the new locomotives havesmaller driving wheels and lower boiler pressure than theMikados, but the cylinders are one inch larger in diameterand they have a starting tractive effort almost 4,000 than the Mikados. ^t is evident that there is a con-siderable sacrifice in heating surface; there are eight lesssuperheater units and 20 less tubes, and they are 4 ft. 2 than those in the Mikado type boiler. The differ-ence in grate area is less marked. For heavy drag service,however, high tractive effort at slow speeds is the controllingfactor rather than a high sustained horsepower p. & R. Consolidation Type Boiler enlarged dimensions, is used in the new design. The fuelgenerally used today consists of a mixture of fine anthraciteand bituminous coal, and this is burned on a rocking grate,instead of on a combination of water tubes and pull-out bars, •as applied to the earlier locomotives. The new locomotives are designed for heavy drag service. The boiler has a conical ring in the middle of the barrel,which increases the diameter from 79^4 in. at the first ringto 85% in. at the throat. The firebox has a combustionchamber 39 in. long, and a brick wall 26 in. high is builtacross the throat of the chamber. Flexible bolts are usedalmost exclusively in the water legs, and four rows of ei- 175 176 RAILWAY MECHANICAL ENGINEER Vol. 93, No. 4
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
