I wish I still had it, but many years ago I had a 117 standard gauge caboose that had one window high, other was low on one side. Confirms errors on cabooses, most errors are in window placement. From my Marx Trains production experience, windows are often a separate punch operation, so the main die can be used for multiple car types. Because of this, there is more opportunity for error in placing the car blank in the die incorrectly, or getting distracted and forgetting to punch one side. I have some of our Marx error pieces, and most are windows being punched on the wrong location on a caboose. Also have a boiler for the Disney loco where 2 sets of punches were made for the domes and stack on the top.