638

MODERN STEAM PRACTICE.

placed on the top of the tank at the back end, the principal useof which is for filling the tank with water, but it is also made ofsufficient size for a man to pass through to inspect the inside ofthe tank.

Two feed pipes are fitted to the front end, and are coupled to thefeed pipes from the engine. They are provided with valves forregulating the supply.

It is highly necessary that the water used in a locomotive boilershould be as pure as practicable, and for this purpose all impuri-ties should be got rid of in the reservoir before the water entersthe tank.

TPIE AMERICAN TENDER.

The tenders for American locomotive engines are very differentfrom those of the British type. The tank is of the ordinary form,and contains from 1200 to 2000 gallons of water, and from 1 to 3cords of wood fuel, occupying a space of 128 to 384 cubic feet. Theframing under the tank is constructed of wood, the whole of theweight being carried on two trucks similar to that of the engine;in the forward truck the weight is carried on the centre, and at theback end the load is carried on the sides of the truck; by this meansthere are three parts on which the load is supported. The brakegear is very powerful, each truck carrying its own System of brakes;the willow blocks are secured to transverse bars of wood, and arecarried up with shackles secured to the truck frames, and whichare actuated by means of a handle and spindle for a chain windinground, taking a System of levers on the front truck, which drawsthe willow blocks forcibly against the wheels, with a similar Systemof levers for the back truck, which is connected to the forwardSystem with a chain; by this means the trucks can swivel withoutderanging the mechanism. In some examples the brakes are onlyfitted to the back truck of the tender, and are suspended from theframing. The trucks have each four wheels with axles, havingthe necessary axle boxes, the guard plates are of cast iron boltedto the frame; the springs are placed on the top of the framing, towhich they are secured with suitable harness. A strong chain andshackle is placed at each top corner of the truck frame, the otherend being carried by the main frame; these are necessary in orderto prevent the trucks swivelling too far.