How does tracker action connect an organ key to a pipe?

Tracker action is a mechanical system that creates a direct physical link between an organ key and the pipe it controls. When an organist depresses a key, the motion is transmitted to a pallet valve—which admits air into the pipes—through a series of cranks, levers, and rollers.12

The system bridges the distance between the keyboard and the wind-chest using trackers, which are thin, tensioned strips of wood, metal, or plastic. Because this mechanism provides a direct connection to the valve, it is highly valued by many organists for offering superior sensitivity and responsiveness compared to pneumatic or electric actions. However, on larger instruments, this mechanical linkage can require significant manual strength to overcome the wind pressure against the valves.12