the protruding portions of the wheels. The platforms, angle irons, and brackets are riveted on by means of portable hydraulic riveting machines similar to those used in the boiler shop.
Erecting the Motion. The cylinders and motion plate being in position the slide bars may now be fixed. For this purpose the wires cc (Fig. 42), representing the cylinder centre lines, are used, and from these the erector can set the bars parallel to the centre lines and equidistant from them above and below. The bars are bolted to faced projections on the back cylinder covers at one end and on the motion plate at the other. Thin brass liners are placed between the bars and these projections, their thickness being adjusted to suit the proper distance apart of the bars. The pistons, with their rings sprung into place and with the piston rods attached, are put in from the front end of the cylinders, and the crossheads are then attached to the piston rods. The crossheads with their slide blocks act as guides in setting the slide bars, between which the slide blocks must work up and down quite freely, but without shake.
The slide valves are placed inside their buckles. These are rectangular frames forged solid with the spindles which pass through the glands in the ends of the steam chest covers. The buckles or frames simply embrace the valves, so that when the spindles are moved by the valve gear, the
