Hi Troley_lover.
These trolleys are the quietest I have ever heard. Outside you hear nothing, inside you just hear the transmission from the traction motor to the wheels. Very , very quiet. You will be amazed. When they run using the diesel generarator, there are VERY noisy. Yes the trolley booms (what you call pantographs) are controlled by pneumatic devices. They can be lowered or put on the wire at the touch of a button from the driver's seat......So the booms can be put into contact with the electric line IF there is this sort of device on the electric line:
