Great. Let them publish and post how-to videos. I'm just the messenger here, not the one that made the statement.
It's been a few days since I saw the video and I've slept since then. I don't recall if the designer said that it was due to weight. I do know that he said that, if they removed a carriage car, that the train ran great. Add the car back and nada. Since the train looked terrible with a car removed, they gave up on selling the set motorized. However, he followed that statement up immediately by saying that he was sure that an enterprising AFOL will solve the problem right away and that he wishes them luck.