I agree, as I posted over at Trainboard.com, that I was surprised by how well the new Athearn husky-stacks run despite their light weight (although they are heavier than the old roundhouse/MDC stacks which were constantly off track even with a weighted container). Even empty they ran perfectly through some "problem" areas of my track. Got to give credit where it is due, they improved the old model, maybe with the body mounted couplers/trucks and mchenrys?
Jan