So apparently the X’Trapolis trains have some form of battery. I saw one just drop its pantograph, yet the lights inside were kept on. I guess that makes sense, as there needs to be a way to raise its pantograph back up again.
I guess it’s like a car with an internal combustion engine. Obviously you can’t drive it on battery alone, but you can operate lights and the radio.
This shouldn’t be a revelation to me, but for a long while, I always wondered how they got the pantograph up. Did they use something like a pole or crank? Nah, it’s just a battery.