That helps after the fact but sometimes that isn't posted until 6 months after release and in some cases like the J3a Hudsons never. Would be nice to know before committing.
Oh for sure. Zooming in on the chassis usually tells you nothing, as the pictures aren't great.
I'm in the process of acquiring one of the Legacy ATSF 3751 class Northerns from the 2019 run. I'll soon enough find out if it has the multi gear gearbox. At least with MTH Premier I know I'm getting a worm wheel and a worm shaft with ball bearings on each end in the gearbox every time, and that's it. Haven't had one issue with that design, and I will sometimes run big 4-8-4s on the front of passenger trains at 75mph for a couple hours.