Lighting today is so easily done with LED's, all my passenger cars and cabooses are powered by a 9v battery and the battery box is mounted under the car. It does have a on/off switch and tucks in very well and looks great. My end cars only have marker lamps which are usually just mounted on one end of the car, so I have no need for direction of the lights, but if I did it could be wired very easily and just the addition of one switch. I personally don't care about track power for lighting, mainly because all my engines, etc. are battery powered, plus I have no light flickering which looks funky.
trainman