The Locomotive Of Today

The Engine : Crossheads, Connecting Rods. liable to slightly distort the metal. The slides should be amply lubricated to ensure easy working, and also to keep them free from dust and grit, which is very liable to get upon the bars whilst the engine is running. A crosshead used for the Vauclain compound has tour slide bars, the high and low pressure cylinders being arranged one above the other with a separate piston and piston rod tor each. These are connected at their outer ends to a common crosshead which has two sockets to receive them, one above the bars and one below. The bars are arranged similar y to those shown at F, with the centre of the crosshead swelled out and sliding between them. This is cast in one piece of Steel, and the wearing surfaces are covered with block tin inch thick. Other American forms resemble that at A, excepting that the wearing strips or “gibs” are provided at top and bottom with means by which they can be set out to take up wear. . 1 . . . , . The connecting-rods are the mediums through which tne reciprocating motion of the crossheads is converted into rotary motion at the cranks, and consequently the wheels; at one end they work upon the gudgeon pins of the crossheads, which have been already described, and at the other on the crank pins. Various designs and shapes for the ends are m vogue, experience having taught that the end of the rod nearest tie crank is the most liable to breakage when working, and therefore this end is always made the stronger, and being the larger of the two it is known as the “big end,” whilst the other, or crosshead end, is called the “small end.” It has also been found that welds are unsafe, it not being always certain to make a good job of such a large weld, accorcling y rods now, when of wrought iron, are always forgecl from one “bioom,” welding being entirely eliminated. Cast Steel is largely employed for connecting rods, but whichever metal is used, great care is taken in examination, to prevent defective rods being put under an engine, as it is most important tnat none but the best metal and workmanship be allowed in these important members of a locomotive, the breakage of which is liable to be one of the most disastrous failures that can occur to an engine when running. Ihe section is generally rec- tangular with the' corners well rounded off, but. some small engines have them round, and when cast steel is used they are often made fluted, or of H section, this giving the greatest strength for the area of metal employed, and also allows tor some reduction in mass, and consequent lessening’ o te reciprocating weight. Ihe area of the cross sc^ction o meta at the centre of the connecting-rod is by empirical rule, made