A. The positive binding posts, both at the dynamo and the lamp, have been provided with a much larger hole to receive the wire than has been made in the negative binding posts, and the ends of the positive wire should always be bent or doubled back, so that they will just enter the receptacle in the positive binding posts, but cannot be connected at the negative binding posts.

28.  Q. Should the copper electrode and holder become fused until no longer serviceable while on the road, what would you do?

A. Would remove the damaged holder from the lamp and substitute either an iron bolt of sufficient length or a carbon, securing the improvised electrode in the bracket of lamp same as the electrode holder is held, only being sure that the end of the bolt or carbon comes up into the center of the reflector and did not rest on the base of reflector or lamp.

29.  Q. What is the difference between a series wound equipment and a compound wound equipment, and what advantages are obtained from the use of the compound equipment.

A. With the series wound equipment, the incandescent cab lights burn only with the arc lamp, while with the compound machine the incandescent lamps are independent of the arc and can be used as desired.

30.  Q. If you were running along with your light burning steadily and nicely, then suddenly the light began to flash badly and kept it up, where would you look for the trouble?

A. Trouble would usually be found at one of the binding posts, where one of the binding post screws would be found loose.

31.  Q. If you were running along with light burning satisfactorily and suddenly it went out, where would you be likely to find the trouble?

A. You would find that either the carbon had burned out, one of the lead wires had broken between the dynamo and the lamp, or one of the wires had gotten loose at the binding post and fallen out.

32.  Q. If the light goes out while you are between stations, what course should an engineer pursue?

A. If the light goes out while you are between stations and an investigation cannot be made within a few minutes thereafter to determine the cause, the steam should be shut off from the turbine and the dynamo stopped until such time when the cause of failure can be determined.

33.  Q. Why is it essential to shut off steam and stop the equipment?

A. For the reason that if the failure was due to a short circuit, damage might be done to the coils or armature by overheating.

34.  Q. How does the equipment act when short-circuited?

A. When there is short circuit, the engine will labor heavily, run slow with a large volume of steam blowing at the exhaust, there will be no light shown either at the arc or cab lamps, and the carbon point and cab lights will only show a dull red or go entirely out.

35.  Q. How will the equipment act when the circuit is broken, either by a broken disconnected wire or a burned-out carbon?