been keyed on at the proper angle to the crank axle in the wheel shop, and nothing remains to be done but to place the straps and rods in position, and couple the latter to the links of the link motion, which are put up at the same time and connected to the valve spindles. The brackets on the frames which carry the reversing shaft are bolted into place temporarily, but are not fixed permanently until the valves have been set, this being the next operation, a description of which is given in the following chapter. For the moment it will be supposed that the valves have been set. The coupling rods are then put on to the pins in the wheels. These rods are formed at the ends with simple circular brass or white metal bushes which are pressed into the holes in the rods by hydraulic pressure. Formerly double brasses secured by cotters, somewhat similar to those used for connecting rods, were used for the coupling rods, but they are now almost obsolete in this country, though still used to a large extent on continental and American engines. To prevent the coupling rods from being thrown off the wheels, washers are placed on the ends of the coupling rod pins, and secured by nuts and taper split-pins.
Only miscellaneous work now requires to be done to complete the engine. The firebars are placed on their bearers in the firebox, and the ashpan is bolted up underneath the firebox. The brake gear has also to be rigged up with all its attendant levers, and the cylinder cocks and
