After AMT and KMT manufactured these boxcars, Andy Kriswaulis acquired the tooling and made lots of cars. I'm certain that some of the CHOO-CHOO BARN boxcars displayed by the yard and house on fire there are his. He made cars in short runs, and they varied. Every CHOO-CHOO BARN boxcar or reefer (a plug door) has slightly different graphics. Generally, the type face (stamped lettering) remained the same but it was applied in different places. Body colors varied, too, though most CHOO-CHOO BARN cars were yellow. The number - 1616 - is the house number of the now-defunct train store in Allentown (north of the fairgrounds) where these cars were sold.
Another manufacturer that used the same tooling was Precision Valley Products / Newbraugh Brothers Toys (PVP / NBT) in West Virginia (I think). As time went by, graphics became much more sophisticated. Here is a PVP / NBT boxcar made in 1990, one of a series of freight cars made for Schuylkill Haven Borough Day. A passenger set of K-Line streamliners and FA units was also made.
Sometimes PVP or NBT was cast into the tiny board to the right of the ladder on one end of the car. But, like the NH&I car, neither of these cars has a manufacturer's mark.
