alot of people complain that the doors dont open on these cars, but as far as i am concerned, they dont need to open…these are possibly one of the finest, plastic models of a box car made today but they do have a couple of issues (again, my interpretation only)…the first and most important, are the ‘caps’ that fit over the axel ends and ‘spin’ with the wheel/axel assembly…great feature, but very hard to notice as the train i going by, unless you are down LOW, looking for them…but the big issue with these happens if there is a derailment or crash…these damn caps go flying, never to be found again…yes, i know, GLUE the caps on…but IF you change the wheels (second issue) then that just aggrevates the situation…my answer to this quandry would be to have SLIGHTLY tighter fitting caps…now for the second issue…aristo, (i imagine to boost sales, and not a bad idea) occasionally (usually for special train shows) will sell plastic wheeled Evans cars and 100 ton hoppers for about half the price of a metal wheeled version…certainly a great deal that is hard to pass up…but the problem of what metal wheels will actually fit the roller bearing trucks, to replace the plastic ones, comes into play…aristo MAY have the proper wheels in stock as of this writing, (i dont know for sure either way) but if you find yourself in this situation, here is what i found works…on my aristo streamliners, i replaced the stock metal wheels with LGB ball bearing wheels (BEST wheels on the market IMO) as well as lowering th cars…well, the stock wheels are a PERFECT replacement in the roller bearing trucks with enough of the axel ends extending past the side frames, to install the roller bearing caps (which still could have a tighter fit IMO)…