Riding the Arc: The Tribology of High-Speed Rail Pantographs

Running a massive steel train at 200 miles per hour requires an enormous amount of continuous electrical power. Delivering that power means dragging a metal arm (the pantograph) across a live, high-voltage overhead wire. At those incredible speeds, the aerodynamic bouncing and intense physical friction should instantly shatter the arm or melt the wire. The only thing preventing this is the extreme...