In combination with a transport mechanism that includes a plurality of conveyor rollers, an apparatus is used to position a carriage loadable with a wound reel at a desired location on the transport mechanism. The apparatus includes a rotary pulse generator associated with one of the plural conveyor rollers for registering the revolutions of the one of the plural conveyor rollers wherein the revolutions embody a measure of the distance traveled on the transport mechanism by the carriage. The apparatus also includes at least a first and a second initiator for determining the current position of the carriage on the transport mechanism. The first initiator detects a first position of the carriage. The second initiator detects a second position of the carriage. The revolutions of the rotary pulse generator and a distance between the first and second initiator are used to calculate a slip (K), which is used to determine distance (W) between the current position of the carriage and the desired position (S) of the carriage.