I don't know for sure but I do have a theory:
Due to the rolling stock of the TMR's being so flimsy, short and light weight coupled with all the roller coaster type sets, I believe the toothed wheels tend to help those stay on track especially going downhill and on curves. In other words they can track easier behind the engines.
Due to the rolling stock of the TMR's being so flimsy, short and light weight coupled with all the roller coaster type sets, I believe the toothed wheels tend to help those stay on track especially going downhill and on curves. In other words they can track easier behind the engines.
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