Apparatus for automatic adjustment of guide rails for guiding articles on a conveyor via lanes is provided. The apparatus includes spaced apart first and second tracks, a carriage for driven travel along the first track, and a guide rail hanger for select slaved travel along the second track by the carriage in furtherance of lane adjustment. The guide rail hanger is operatively linked with a guide rail hanger positioning bar for select reversible affixation with respect thereto in furtherance of establishing a fixed guide rail position relative to the conveyor. A latch assembly, supported by the carriage, has a latch selectively operable for captured carrying of the guide rail hanger along the second track during travel of said carriage, the latch effectuating release of an affixed guide rail hanger from the guide rail hanger positioning bar in furtherance of enabling relocating and re-affixing the guide rail hanger relative to the guide rail hanger positioning bar in advance of captured carrying thereof.