Gear Train
The series of wheels and pinions that transmits energy through a watch movement at controlled ratios.
Also known as: wheel train, going train, train of wheels, geartrain
Definition
The gear train is the sequence of wheels and pinions that carries energy through a watch movement at calculated ratios. In a conventional mechanical going train, power passes from the barrel through intermediate wheels toward the escape wheel. The ratios determine rotational speeds: for example, the fourth wheel commonly turns once per minute in a traditional layout and can carry a seconds indication. Separate motion-work gearing converts movement rotation into the hour and minute display. Tooth geometry, pivot friction and alignment all affect efficiency.
Why it matters
The gear train connects stored energy to both regulation and display. Its efficiency, ratios and condition affect power consumption, amplitude and reliable operation, while its layout is fundamental to movement architecture.