53.  Q. What provision is made for moving or focussing the lamp in the reflector?

A. When the lamp is mounted horizontally there are thumb screws by which the lamp may be moved sidewise, up and down, and forward and backward.  This mounting is called the “micrometer” device, because of the accuracy of adjustment.  With the vertical mounting, a flat head thumb screw at the base of the lamp support releases the ball joint so that the lamp may be easily moved sidewise or forward and backward.  To raise or lower the lamp, the thumb screw higher on the lamp stand must be loosened.

54.  Q. What causes a “black spot” in the illumination ahead of the locomotive?

A. The lamp is out of focus, being too far ahead or back of the proper position in the reflector.

55.  Q. How would you remedy the following possible defects?

A. (a) =All lamps fail to burn.= If turbine is not running the wrong steam valve in the cab may have been opened, or there may be a second valve, closed, in the steam pipe.  The screen on the governor valve in the turbine may be clogged.  Remove brass cap at top of turbine and unscrew screen or strainer-cap.

(b) =Turbo-generator runs, but no lights.= Wires may be “short-circuited” (crossed) which will cause brushes to spark badly, and turbo-generator to pull hard.  The “short” can usually be found by an occasional sparking or smoke at the point of trouble.  Separate and protect wires when short is found.  The brushes may be “cocked up” as left by some repair man.  Open the dynamo door and see that the brushes bear on the copper commutator.  A wire may be loose at the dynamo binding posts (which may be seen when the dynamo door is open), or at the main switch in the cab.  A main wire may have broken. (All locomotives are not equipped with fuse plugs.) A fuse plug may have become loose or burnt out.  Replace with new fuse plugs or break an incandescent lamp and twist the leads in the base together, when the base may be screwed into the fuse plug socket, answering the purpose of a fuse plug, temporarily.

(c) =Headlight fails to burn.= Examine the wires between cab switch and head lamp for breaks or disconnections.  Examine fuse plugs (which are sometimes in head lamp circuit only) and proceed as in (b) if trouble is found there.  Headlight bulb may not be screwed in far enough to make contact in the socket, as the lock-sockets provided to prevent lamps loosening cause lamp to screw in hard.  Lamp may have broken fillament.  Replace with proper type of lamp or use a cab lamp.

(d) =Lamps burn dim.= Steam valve not open wide enough.  Boiler pressure too low.  Brushes sparking badly on commutator of dynamo—­due to poor contact.  Governor or steam-valve of turbine improperly adjusted.

(e) =Lamps burn too brightly.= Improper turbine regulation.  Throttle the steam valve in cab until lamps are reduced to proper brilliancy.  Report all irregularities on arriving at terminal.