The Locomotive Of Today

The Engine: Stationary Link Motion. 93 quadrant blocks, and arms above to work the valve spindles. With the valves below it is usual to incline the faces upwards to the centre line of the axle. When the faces are inclined either above or below the cylinders, the eccentrics are not altered with regard to each other, but both are simply shifted round the crank until the centre line of the whole four, which in the illustration is coincident with the centre line of the piston, is upon the centre line of the inclination when the crank and connecting rod are upon their centre line. If a rocker is used, the eccentrics have to be placed reversed on the axle relatively to the position of the crank. Thus, if the crank is placed horizontally, and no rocker is used, the eccentric is put upon the side of a vertical line through the centre of the axle, furthest from the crank pin ; but upon the side nearest the pin when the rocker is employed, as it alters the relative movements of the valves with regard to the pistons. The rocker is sometimes used on British railways and is universal in American practice. The stationary link, or Gooch motion, as applied to an outside cylindered engine, is illustrated by Fig. 19. In this, two eccentrics are placed as before upon the driving-axle, but as there are no crank webs by which it would be possible- to secure them, as in inside cylindered engines, keys must be employed. The eccentrics and straps are here shown of a different construction to those in Fig. 18, the large portion of the eccentrics being of cast and the smaller portion of wrought iron as before, but set screws in addition to the keys are shown. The straps are of wrought iron and are recessed on the inside to receive a cast iron liner made to fit and so prevented from having side movement; to keep them from turning in the straps, the latter are made in two portions and distance pieces are inserted at the junctions of the straps and project down to the sheaf, and the two half-liners butt upon them. These dis- tance pieces serve another purpose, as they can be reduced in thickness when it is found necessary to let the liners together to. take up wear. It is not usual to use these distance pieces when the straps are entirely of cast iron, as these can be let together,. they being scrapped when worn out, whereas the wrought iron straps can be used over again with fresh liners. The butt ends. of the eccentric rods are secured to the straps by studs. Oil cups are forged upon the straps and fitted with oil syphon pipes. Of course, it will be understood that the other methods. of building up the eccentrics and straps can be equally well applied to the stationary as to the shifting link motion. The link itself is of the “box link” type—it consists ot two channels of the proper section and curvature required,