44. Q. What is meant by an incandescent headlight equipment?
A. A headlight having an electric incandescent lamp in the reflector in place of the usual oil or acetylene gas flame, and electric instead of oil cab lamps, the electricity being generated by a small combination steam-turbine and electric generator. Suitable wiring distributes the electric current.
45. Q. In what manner does the incandescent headlight differ from the arc headlight?
A. It is not so powerful. An incandescent or bulb type of lamp takes the place of the arc lamp in the headlight reflector. The current being less than is required for an arc, is supplied by a smaller turbine.
46. Q. What type of incandescent lamp is used in the reflector?
A. A low voltage, gas filled bulb, containing a very compact or concentrated fillament.
47. Q. Why cannot a standard or house type of lamp be successfully used in the reflector?
A. Because the fillament or light-giving wire inside the bulb is not sufficiently compact or concentrated to reflect the light in the form of a beam. The voltage of the house lamp is also too high to be used on a locomotive installation.
48. Q. How is the lamp held in place in the reflector?
A. By the usual socket, into which the lamp screws. The socket is a part of the focusing device, one type of which holds the lamp in a horizontal position, while in the other the lamp is held vertically or upright.