A. It lengthens the distance between the eccentrics and rocker pin.

Q. What characterizes the pound caused by a loose pedestal brace or bolt?

A. It takes place on only one center,

Q. What is the usual wear of a main journal, that causes pounding?

A. Flatted on one side, or oval.

Q. If pound is in the wedges, how can you set them up and get them right the first trial?

A. By pinching the wheels away from the wedges, screwing up the loose wedge, then trying if the box slides freely without shake; then slacking off a trifle to keep the wedge from sticking when warm.

Q. Will an engine pound if pedestal bolts are loose? If so, why?

A. Yes, because the pedestal works loose and draws down the wedge.

CHAPTER LXXXII

REPAIRS

Q. Into what classes may repairs be divided?
A. Running or "light," and complete or "heavy."

Q. How often should boilers be overhauled and retubed?

A. Every four or five years.

Q. How often should the fire-box, tubes, etc., be examined?

A. About once a month.

Q. And the injectors?

A. About monthly, according to the water used.
Q. Wheels and axles?

A. After a certain mileage, according to speed and weight; say 3,000 to 4,500 miles.

Q. In stripping an engine what precaution should be observed?

A. As far as possible to note or remember the exact order in which parts are removed so as to replace them in the same order; also where possible to remove groups of parts, separating them afterwards; if the parts are not stamped "R" and "L" to stamp them so, and, what is more important, with the engine number.

Q. What care should be adopted in stamping?

A. To avoid vital parts.

Q. What kind of a hammer should be used?

A. Copper, lead or raw hide.

Q. What precaution is desirable in chipping off rivet heads?

A. To chip them into bagging or something similar to prevent their rebounding.

Q. How can the piston rod and valve spindle be removed?

A. By removing the cotters and using a wedge and plug to force out the rod from its seat.

Q. What is the best way to remove a riveted-over crank pin?

A. By drilling an axial hole in it for the spindle of a ring cutter that faces off the riveted-over portion and a small portion of the end of the pin proper; then using a hydraulic press.

Q. How are ferrules removed?

A. By a rod with flared end pushed in from the smoke box; thin end; this flare being of the same outside diameter as the inside diameter of the flue.

Q. Suppose the tube is flattened?

A. Then it may be necessary to take out some neighboring tubes and cut out the flattened portion.

Q. How are copper and brass tubes cleaned from deposit?

A. By pickling in muriatic acid.

Q. How is incrustation removed?
A. By careful chipping.

Q. How can you tell if a side stay in the fire-box is defective?

A. By holding a hammer against the inside end and hitting the outer end a smart blow; if it is sound the first hammer will rebound.

Q. How can scale be removed from the outer surface of tubes?

A. By tumbling in a barrel for that purpose; their mutual friction removing the incrustation.

Q. How is soft-patching done?

A. The surface should be well cleaned, the fittings filled with iron cement, smoothed off; the area covered with red lead or graphite paste and the patch bedded down hot and riveted-not bolted.

Q. Why not bolted?

A. Bolt heads obstruct the waterway and facilitate lodging of incrustation about them.

Q. Should cracks be patched?

A. No, as they may extend beyond the patch.

Q. Should bulges be hammered or pressed into place? A. Pressed.

Q. What is a dumbbell patch for tube plates?

A. A patch of dumbbell shape, at right angles to the line joining the tube centers, fitting snugly against the ferrules, and fastened by screws to the tube sheet.

Q. What is a spectacle patch for tube sheets?

A. One fitting snugly around adjacent tubes and having two holes coming fair with the ends of the tubes between which there is a crack; it is fastened to the sheet by 10 tapped-in screws.

CHAPTER LXXXIII

MILEAGE AND RUNS

Q. How long should an engine run before the valves need facing?

A. That depends on the road, on the engines, on the service, and on the engine runner. On the N. J. C. and the P. & R., John Cline made with engine No. 172, 82,000 miles before the valves needed facing; this engine having the Allen valve, balanced. Before balancing the valves, it was hard to get engines of the same lot to run 20,000 without facing. Engine No. 165, on the same road, John Rhodes on the foot plate, made 13,411 miles on express train running before the engine was jacked up, the firebox needing no work and the principal boiler work done being taking out and resetting the flues.

Q. Give an instance of locomotive mileages in regular service?

A. On the N. Y. C. & H. R. R. R., engine 84 after coming out of the shop, was put on the Chicago Express, running from New York to Albany and back, seven days per week, 284 miles a day, with two crews; D. Caffin one day and E. Stamford the next. Before any work was done to fire-boxes or flues she had run 26 months, making 165,000 miles; and then got only light repairs to machinery, and nothing to heating surface; the water used not being good. She had Buchanan fire-box.

Q. Given a road with 1.25 per cent. grades 2 to 2.5 miles long; what engine weight would be needed?

A. Referring to Fig. 398: the maximum trailing load would be 7.7 times the engine weight, or 220 tons, with natural ventilation.

Q. Suppose the ends of the electric line have considerably different elevations?