"My son really likes pushing his numbers train around on Duplo tracks, so I thought he would like an expansion set for the basic set of tracks he already has. I knew that the "action piece" from this set wouldn't do anything with a simpler train, but I didn't realize that the train literally would not fit on the tracks. It's really frustrating that there are no track expansion sets available to push a non-motorized train around on, which kids love to do! I guess I will switch from DUPLO to a wooden BRIO-style track system. Not sure why Lego has chosen to make their train system have so many compatibility issues. Unfortunately I wouldn't recommend this kit or even the DUPLO train system more generally speaking."