Here's what NSK has to say about these -
Santa Fe used one or two head-end mail cars on their "Chief" and "Grand Canyon" passenger trains between 1962 and 1967. These cars were converted from old heavyweight cars (bodies stripped and underframes decked with wood). The cars were loaded with 20' mail containers and were numbered 200-226.
The N Scale Kits car has a cast pewter chassis (lead free) with etched grabs, and laser cut wood decks. Price $23.99.
The 20' mail containers for this unusual car are available from Stone NScale Creations -
