Wheel train

[2] However, the wheel trains of clocks and watches share the same terminology, and are similar enough that they can be described together.

This allows the use of a very strong, slow turning mainspring or heavy weight that will run the timepiece for days or weeks.

The going train in a modern clock or watch consists of: The motion work is the small 12-to-1 reduction gear train that turns the timepiece's hour hand from the minute hand.

[6][7] It is attached to the going train by the friction coupling of the cannon pinion, so the minute and hour hands can be turned to set the time.

[8][9] The term originated because, before the modern form of keyless works was invented by the French watchmaker Adrien Philippe in 1843, watches were wound and set by inserting a separate key into holes in the back and turning it.