Hello all - first post here from a relative newbie.  I've been expanding my O scale layout over the past several years, adding additional track and accessories.  I recently added a Lionel Reindeer Corral and operating car 6-36704 and am having a power issue.

The portion of the layout with the Corral is a simple oval section that is not connected to other parts of the layout (i.e. no switches to other track, etc.)  I'm using Fastrack for the oval except for the section connected to the Corral with uses traditional O scale tubular track; I've used Fastrack transition pieces on the transition.  Oval is powered by a basic Lionel transformer 40W Powermax 6-81495.  I've wired the corral and operating car on the tubular track per the instructions in the accessory manual, using OTC and CTC lockons and standard Lionel toggle switch.  The accessory and lockons are connected to / powered by a Lionel accessory transformer - basic 1.8 amp 6-32923; operated with a simple dial to adjust voltage.

Issue is this: the car and corral work perfectly, doors open, reindeer vibrate, load and unload, etc.  Problem is that as soon as any voltage is applied via the accessory transformer, any powered unit on the track also begins to move.  Even with the main track transformer shut down, and regardless of the position of the toggle switch that activates the accessory.  Any thoughts on how to correct this?