I have a MTH ABA E-8 that has a derailing problem. The blank wheel sets do not slide (left-right) over the rail surface allowing the truck to negotiate (any radius) curve. The blank wheel sets rides up, and fall between the rails causing a derailment. I have other MTH 6 wheeled diesels, with blank wheel sets, that operate flawlessly. Did MTH have a bad run of 6 wheel trucks at one time?
Is there a remedy for this problem?