thanks for clarifying. My layouts almost always allow for reversing loops. On 2018's Christmas layout I even made the tracks that the engine in question was running on connected to the tracks that my Baby Blue Comet tin-plate set was running on. The Comet ran fine on either set of tracks while the "christmas train engine" couldn't pull 4 cars on either set of tracks.
This has been this way for the last 3 or 4 Christmas layouts.
thanks - walt