A MeccParts geared motor drives the central carrier shaft via a heavy, but readily slippable, O-ring. The outer carriers rotate at 4/5 the speed of the central carrier. As they are 2 1/2" in diameter and the central carrier is 2" in diameter, their rim speeds are nominally the same - this makes switching spool assemblies from one carrier to the next very straightforward. The gearing to do this is mounted in pairs of strips seen here at an angle to everything else.

The drives to the take-up drum at the front and the overhead pinch rollers is taken from the LH carrier shaft via its 12t helical seen here in lowermost position.