have point of
copper electrode as near the center of reflector as possible with
carbons as near the center of chimney hole as you can set them. (3) Have
the locomotive on straight track. Now move the base of the lamp around
until you get a parallel beam of white light straight down the center of
the track, then tighten lamp down.

36. Q. If the light throws shadows upon the track, is it properly
focused?

A. No.

37. Q. If the light is properly focused, that is, if the rays are
leaving the reflector in parallel lines, but the light does not strike
the center of the track, what should be done?

A. When the light rays are thrown out in parallel lines and they do not
strike the center of the track, it denotes that the headlight case is
not set straight with the engine, and the entire case on baseboard must
be shifted until the shaft of light strikes the track as desired.

38. Q. What can you do to insure a good and unfailing light for the
entire trip?

A. By carefully inspecting the entire equipment before departing on each
trip and know that there are no wires with insulation chafed or worn
off; that all screws and connections are tight; commutator clean;
brushes set in brush holder in the proper manner; carbon in lamp of
sufficient length to complete trip; copper electrode cleaned off and oil
in both bearings.

39. Q. Why would you not fill the main oil cellar full of oil?

A. If you should fill the main oil cellar full of oil, the oil would run
out of the overflow holes on the side and all over the equipment and
locomotive and could do the dynamo no good but possibly harm.

40. Q. What is the most vital part of the dynamo?

A. The commutator.

41. Q. What care and attention should be given the commutator?

A. The commutator must be kept clean, free from dirt and grease; the
mica must be kept filed down about one-sixty-fourth of an inch below the
surface of the bars.

42. Q. How should you clean the commutator, and when?

A. The commutator should be cleaned before starting out on each trip by
using a piece of damp waste, rubbing the bars lengthwise, then wipe dry
with clean dry piece of waste.

43. Q. What kind of a bearing should the brush have on the commutator?

A. Brushes should be fitted to have a bearing with the same contour as
the commutator, with bearing covering no less than two of the commutator
bars, nor more than three of the bars.

44. Q. How are the brushes fitted?

A. Brushes are f