Abstract: A conveyor system (10) is disclosed comprised of a plurality of vehicles (12), propelled about a guide track (14) by a D.C. motor (54) and battery (52), featuring an on-board control (40) in which signals from fore and aft and side mounted photosensors (32,34,36,38) are processed by a microprocessor (42), to generate control signals for pulse width modulated control of the power to the D.C. motor (54). The control signals are applied to a motor driver circuit (50), including an H-bridge of MOSFET switching components (Q1,Q2 A ramping or progressive variation of the power applied to the motor (54) is carried out to provide gradual acceleration or deceleration, and the fore and aft photo-detectors (32,34) are triggered by the approach of another vehicle (12) at a substantial distance, to accommodate the distance required for gradual deceleration when the vehicles (12) are being queued at points along the track (14).