64. Q. How would you proceed to locate the point of trouble with a short circuit?

A. Would remove (1) one of the lead wires from the binding post at dynamo; if trouble was in dynamo you would not note any difference in action of speed. (2) Would disconnect one of the cab wires; if the trouble is in cab circuit, speed would increase and lamp would burn. (3) If trouble is not in cab circuit, would go to lamp, disconnect one of the main wires from binding post; if short circuit is in the wires between dynamo and lamp, there would be no change in speed of dynamo, but if the wires are O. K. the speed of engine would increase and your trouble would be in the lamp.

=DUPLEX LOCOMOTIVE STOKER=

1. Q. Of what does the driving mechanism of a Duplex Locomotive Stoker consist?

A. It consists of a steam cylinder with reverse head and valve arrangement similar to the steam end of an eleven inch Westinghouse air pump.

2. Q. How is the power controlled?

A. The speed is variable, and by turning the valve controlling the engine steam inlet, can be made greater or less according to the amount of coal needed.

3. Q. For ordinary operation, how much steam pressure is required?

A. About fifteen pounds, with piston strokes varying from 10 to 15 per minute.

4. Q. How can the duplex stoker driving engine be started, stopped, or reversed?

A. By means of operating and reversing rod, fastened to the back head and connected with the valve on reverse head of engine cylinder.

5. Q. How can the conveying screws be started, stopped, or reversed separately or together?

A. By ratchet and pawl arrangement controlling each.

6. Q. What practice should be followed in building up the fire before leaving a terminal?

A. Build up a light even fire by hand and do not bring stoker into use until the locomotive is working steam.

7. Q. How should the stoker be oiled and operated?

A. It should be thoroughly oiled before leaving the terminal, then see that operating rod on back head is in center or running position, open main jet line so they register about fifteen pounds on the jet steam gauge if coal is coa.r.s.e, or ten pounds if coal is small. Next, the driving engine steam valve should be opened wide and the throttle valve opened just enough to supply the proper amount of coal to the fire-box.

8. Q. How is the distribution of coal over the grate area accomplished?

A. By means of a low-pressure constant steam jet located in the back and bottom portion of each distributor elbow, as indicated by its individual pointer on steam gauge.

9. Q. By increasing the jet pressure, will more coal be carried to forward end of fire-box and against the flue-sheet?

A. Yes, it will, and by decreasing the jet pressure more coal will be fed at middle and back end of fire-box.

[Ill.u.s.tration]

10. Q. Can the fireman direct the even distribution of coal in the fire-box?

A. Yes; by changing position of the dividing rib located in the transfer hopper, and by moving the regulating lever to either side.

11. Q. Should the sliding plates at the bottom of the tank be closed before coal is put on tank?

A. Yes, so that screw conveyor will not become clogged and inoperative.

Only one slide should be opened at a time and coal fed from tank as required.

12. Q. In case the stoker becomes clogged or it is desired to reverse it for any reason, what must be done?

A. The operating rod located on the back-head of the locomotive boiler--if the piston is making a power stroke--should be moved to its lower position, and if the piston is making a return stroke, it should be moved to its upper position. This moves a small valve in the auxiliary head, bolted to reverse head, and steam is admitted to opposite head of cylinder, causing the piston to change its direction.

The return of the operating rod handle to a central position causes the driving engine to resume its normal operation.

13. Q. How can the fireman observe the condition of fire in fire-box?

A. The elbows are provided with peep valves with swinging covers through which the coal supply and condition of fire may be seen.

14. Q. Why are two gauges necessary?

[Ill.u.s.tration]

A. The driving engine gauge on the left indicates the pressure of steam used by the driving engine. The one on the right has two indicators, the red indicator showing the steam pressure on the jet in left elbow, and the black indicator showing the pressure on the jet in the right elbow.

15. Q. When train is standing on siding for a short period, what should be done?

A. Shut stoker off by throwing operating rod on back head of locomotive boiler out of running position.

16. Q. When train is to stand for a long time or engine is left at terminal, what should be done?

A. The driving engine should be cut out entirely by closing main steam line inlet and main lubricator connection, and in winter time all drain c.o.c.ks should be opened.

17. Q. If sufficient coal can not be supplied over front grates, what may be the cause?

A. Distributors may be warped and point too low, or steam jets may be plugged with pipe scale and not blowing freely.

18. Q. How would you start and operate stoker?

A. First open main valve No. 1 at steam turret. Valve 2 is then opened; this is the main valve in stoker steam line. Next open valve 3, which allows the steam to flow to the distributor jet line; open valves 4 and 5, which govern the pressure on the jets until ten pound pressure shows on the right-hand gauge. See valve 8 to the exhaust line is open, and valve 9 to the transfer hopper is closed.

19. Q. How would you start the stoker engine?

A. Place operating lever 10 in horizontal or running position. Place conveyor reversing lever 12 in forward position. Open valve 6, which allows the steam to pa.s.s to the operating valve and starts stoker running. Valve 7 is to be used as an emergency valve only in case of clogging. Stoker should be run slowly at first. Do not feed too much coal and carry a light fire.

20. Q. How would you reverse conveyor screw in tank?

A. Lower handle 10 on operation rod on boiler head to bottom position.

Move screw conveyor, reverse lever 12 back to rear or reverse position, raise handle 10 on operating rod to center position.

21. Q. How would you stop conveyor screw in tank?

A. Place conveyor reversing lever 12 in center position.