???Since my foray into N scale has been Bachmann small steam locomotives, that I will admit that only one was purchased "New in box"...and they all except one are 0-6-0 switchers...I have two, that one is a "Park Display" in back of the station, I have one that is packed away because the drivers are out of synch due to loose fit on axle, and I have one that runs...but fast. They are different years of issue so there is small things that I see, but no one problem, other then do not want to run without stop and go or no go. I have the 2-6-2 that I just purchased....the boiler tilts to the front, the rear truck touches the tender, the rubber tires are on the front drivers, (but on another 0-6-0 they are the middle driver....same idea of drive except why the change...because the front drivers having a rubber tire, transfers electric pickup to the last two sets of drivers, which I note, it really only has pickup on the rear drivers !!!) The front truck is too large and touches (and sticks) on the front step-board....the drive train rides only on the rear set of drivers, which means that the engine just spins when more the 4 of your freight cars are applied to it. Last is the 2-8-2 of which the drawbar is too short, causing the tender to derail on a curve, and I have been unable to run it because of that. So, I have a nice railroad, featuring the basic DC powered system, all track is smooth as are the few switches so operation wise, I have two locomotives, plus the four mentioned above, for a 2x4 foot layout, which is designed to stand up behind a door flat, and all buildings and scenery packed in one box. But I just can't purchase another Bachmann engine....they are cute, simple, and idea for a "put-away railroad. I have the feeling that perhaps dealers obtain case lots of questionable ??? engines and cater to the market of older, fixed income purchasers, that are able to afford a 30 dollar engine as outlined above, while the same price through a dealer that is Bachmann Certified, sells for up to $160 dollars !. So how can a customer trust what they are purchasing when there is so many different things wrong with one style of engine ?.
Hmmmmmm ...... in the very first sentence you say that all but one are "used" .........🤔🤔
Now, what could the previous owners possibly have done to those engines? 💥💩👺🐒🌪🔥⚡️☔️
I don't think the Bach Man's product is the problem here.
(Broken record). "Used engines.... buyer beware!" (Repeat 1000 times or until burned into psyche .)
Oh ..... one other thing ..... I have around 40 of the Bach Man's steam engines. All are exceptionally well crafted. Only one engine type presented design issues, and once I figured them out those ran well too.