I take a lot of public transportation. Seems that subway trains often do this weird thing that I think of as a “reboot” where all the lights turn off, it goes silent, then starts back up again (all within about a second or two). It sometimes happens on electric buses too.
I’ve always assumed that it is the carriage losing contact with the electrical supply for a second. Are they designed to do this or is this a malfunction? Anything more you can tell me about it?