What type of fluorescent lighting system is used for nyc subway car lighting and what is the voltage,current and frequency for that?
I have a question of my own, if I may piggyback on the first one in this thread.
Years ago, I noticed that the headliners on subway cars from the R-10's through the R-32's with the narrow side lighting had oval holes in the paneling. The newer cars and the ones that got new lighting in an overhaul process don't have such holes. What was the purpose of those holes?