I'm confused by the images I'm seeing for the new old-time boxcars (I haven't yet seen any "in person"). Do only some of these cars have truss rods, or do all of them? Even here on the Bachmann website, the images of the UP and B&A cars show truss rods, those of the CP, C&NW, and PRR cars do not. Anybody know? Bach-mann? Thanks!