How many subway workers does it take to screw in a light bulb? It sounds like the beginning of the age-old joke, but how many does it take to screw in all the light bulbs in a 722-mile subway system when the old bulbs burn out and need to be replaced? To answer that question, it takes a mind-boggling number of workers. There are so many light bulbs in the subway system that the city still purchases at least 50 different types of incandescent bulbs. The general illumination of the passenger stations is effected by means of 32 Cp incandescent lamps placed in recessed domes in the ceiling. These are reinforced by 14 Cp and 32 Cp lamps carried by brackets of ornate design where the construction of the station doesn't permit the use of ceiling lights. The lamps are enclosed in sand-blasted glass globes, and excellent distribution is secured by the use of reflectors. So, what keeps the city from being robbed blind by people stealing the bulbs? Simple: Light bulbs in the New York City subway system screw in backwards (with left-handed threads) so people can’t steal them to use at home.
