I ran my Polar Express set on my O27 track, a short few years ago. Mine is the older set before the new Blutooth , but still has the sound features from the movie. I cut the plug off of the transformer pack, that plugged into the Fast Track. And I stripped the wires back, twisted them and solderded them. Then I put put the wires in a Lionel lock on. And I also had my old ZW transformer set up, with a Lionel lock on wired to it. If I wanted to run my Post War trains, I put the ZW transformers lock on on the rails. If I wanted to run the Polar Express set, I put the Polar Express lock on on the rails. I did not leave both lock ons on the rails at any one time. Because I do not believe the power sources are compatible.