PART XVII.

TENDERS.

QUESTION 345. _What are locomotive tenders for?_

_Answer._ They carry a supply of fuel and water for locomotives while they are running.

QUESTION 346. _How are they usually constructed?_

_Answer._ Their construction is represented in figs. 204, 205 and 206. Fig. 204 is a side view, fig. 205 a longitudinal section, and fig. 206 a plan of an ordinary tender, which consists of a frame, _A A A A_, made of wood or iron,[82] mounted on a pair of trucks, _T_, _T_. The top of the frame is covered with planks, _B_, _B_, which form the floor of the tender. On top of this floor a sheet-iron tank, _C C C_, is placed, which carries the supply of water. This tank is made somewhat in the form of a letter ~⊃~, as shown in the plan. It is made in this way so that the space between the two branches, _C_, _C_, or “legs,” as they are called, will give room for fuel. Around the upper edge of the tank a sheet-iron rim, _D D_, is riveted, so as to prevent the fuel from falling off when it is filled up above the top of the tank.

[82] The frame represented in the engraving is made of wood. In the plan it is shown by dotted lines.

QUESTION 347. _How is the tank filled with water?_

_Answer._ There is a round opening, _E_, called a _man-hole_, on top. Into this the end of a leather or canvas hose is introduced, which is attached to a stationary tank, at a water station, and a stream of water is then allowed to flow through the hose into the tank of the tender.

QUESTION 348. _How is the water conducted from the tender to the engine?_

_Answer._ To each side of the front end of the tank, one end of a piece of rubber hose, _F F_, is attached, which is connected at the other end to the pipe on the engine which supplies the pump with water. The opening inside the tank through which the water flows to the hose is covered with a valve, which is not shown in the engraving, but which is operated by a lever or handle, _G_. The valve is covered with a hood or strainer, perforated with small holes, which is intended to prevent dirt from entering the hose and thus getting into and obstructing the pump. The hose is connected to the supply pipe by a screw-coupling similar to that used with ordinary fire-engine hose.

QUESTION 349. _How are the flat sides of the tank strengthened so as to resist the pressure and weight of the water?_

_Answer._ They are sometimes braced or stayed with rods or bars, _a_, _a_, and _h_, _h_, fig. 205, extending from one side to the other and from the top to the bottom, and angle or ~⊤~ iron is also riveted to the sides to stiffen them.

QUESTION 350. _How is the tender connected to the engine?_

_Answer._ By the draw-bar, _H_, and coupling-pin, _o_, fig. 205, and also by the safety chains, _d_.

[Illustration: Fig. 204. Scale ¹⁄₄ inch = 1 foot.]

[Illustration: Fig. 205. Scale ¹⁄₄ inch = 1 foot.]

[Illustration: Fig. 206. Scale ¹⁄₄ inch = 1 foot.]

QUESTION 351. _In what respect do the tender trucks differ from the engine truck?_

_Answer._ Chiefly in having the journal-bearings and frames outside of the wheels.

[Illustration: Fig. 207. Scale ³⁄₁₆ in. = 1 inch.]

[Illustration: Fig. 208. Scale ³⁄₁₆ in. = 1 inch.]

QUESTION 352. _Why are the bearings placed outside instead of inside?_

_Answer._ Because they are then more accessible than if they are inside, and the oil-boxes on the axles can be entirely closed over the ends of the axles, so that no oil can leak out, whereas if the boxes are inside, they must be left open at both ends. When the boxes are on the outside, they can be oiled, or a journal-bearing can be removed and a new one put in its place, with much less difficulty than if the boxes were on the inside of the wheels. The only reason why the bearings of engine truck-axles are placed inside the wheels is because they would be in the way of the cylinders if they were outside.

QUESTION 353. _How are the axle-boxes for the tender axle constructed?_

[Illustration: Fig. 209. Scale ³⁄₁₆ in. = 1 inch.]

_Answer._ Their construction is similar to that of a car axle-box, the standard form of which is represented in figs. 207, 208 and 209. Fig. 207 is a section lengthwise of the axle, fig. 208 a section crosswise of the axle, and fig. 209 a sectional plan. _A_ is the journal of the axle, which is inclosed by a cast iron box, _K K_, which is open in front and at the back. The front has a cover, _H_, which is either fastened by a spring, as shown in the illustrations, or is bolted to the box. The axle enters the box from the back, _I_, and has either a wood or leather packing, _J J_, called a _dust-guard_, to keep the dust from getting in and the oil from leaking out of the box. _D_ is a brass journal-bearing, which rests against a cast iron bearing piece or _key_, _E_, which is put in so that by removing it through the opening _F F_, the brass bearing can be raised up high enough to clear the collar, _G_, on the end of the axle and thus be removed in the same way. The lower portion, _L_, of the box under the axle is usually filled with cotton or woolen waste saturated with oil. This constantly presses against the axle, and thus keeps it oiled.

QUESTION 354. _How are the tender trucks constructed?_

_Answer._ They are made of various patterns, some of which have wooden frames and in other cases the frames are made of iron. The truck illustrated in our engraving, figs. 204 and 205, is made of iron and is very similar to the engine truck, excepting, as already stated, the frames are outside instead of inside of the wheels.

QUESTION 355. _How is the tender supported on the trucks?_

_Answer._ It rests on the centre of the front truck and on a bearing, _n_, fig. 204, on the frames on each side of the back truck. This arrangement gives three bearing points, the advantages of which have already been explained. A truck which supports the load which it carries in the centre is said to be _centre-bearing_, and if the load is carried on each side, _side-bearing_.

QUESTION 356. _How are the brakes attached to the tender?_

_Answer._ They are attached usually to the back truck alone, but in some cases to both trucks, and are operated by a wheel, _N_, fig. 204, and a shaft which extends below the tender frame and on which a chain attached to the brakes is wound.

QUESTION 357. _How much water and coal does an ordinary tender carry?_

_Answer._ A tender for a thirty-ton engine carries from 1,500 to 2,000 gallons of water and three to four tons of coal, and weighs from 40,000 to 45,000 pounds loaded. An engine of this kind and its tender therefore weigh about 100,000 pounds, which, being even figures, can easily be remembered.