I’ve heard of plastic gears and cams breaking, my concern is with damage to the motors. My layout is level with 072 curves. The consist is 11 diecast 3 bay (large) hoppers. In this scenario I am pulling with the typical vertical dual can motors geared directly to the trucks (diesels), none with drive shafts. Since the motors require more voltage to pull heavier trains, I imagine they would run comparatively hotter than a lighter consist, particularly when starting from a dead stop. I would think the tractive effort would ease relative to how fast the train is moving,. In my case I like to run very slow, which I presume would require more effort (engine strain) than running at faster speeds? I know to expect stretched and thrown traction tires, my concern is with causing harm to the motors. My typical run time is 45 minutes. Judging by pulling the consist by hand, I am amazed these engines move at all!