The Pantograph

The pendeltåg gets it's power from overhead wires. The apparatus that facilitates electrical contact to the wires is called a pantograph. There's a lot of science that goes into these things. First they are places on the train to minimize the effects of air turbulence. The actual contacts are aerodynamically designed and the spacing is such that the bouncing and loss of contact is minimized. The wires above actually zigzag from pole to pole to get even wear across the pantograph contact pieces.

Some trains have two engines and multiple pantographs. One of the pantographs is used to power the engine, the other for the cooling equipment which runs even when the engines are off to keep debris out.