Tracker action is a term used in reference to pipe organs and steam calliopes to indicate a mechanical linkage between keys or pedals pressed by the organist and the valve that allows air to flow into pipe(s) of the corresponding note.[1] This is in contrast to "direct electric action" and "electro-pneumatic action", which connect the key to the valve through an electrical link or an electrically assisted pneumatic system respectively, or "tubular-pneumatic action" which utilizes a change of pressure within lead tubing which connects the key to the valve pneumatic.
^"Windchests and Actions: Mechanical action". Organ Historical Society. 1998. Retrieved 22 Nov 2024. The terms mechanical action and tracker action are often used interchangeably to identify a mechanical connection between key and pallet in instruments that have slider and pallet chests.
