Vern thanks for your comment on my humble caboose. Marx made the 7" cars in direct response to Unique Lines unexpected entry into the toy train field in 1948. He pressed them into production and had them ready for the Christmas season of '49. Unique turned out to be more a "flash in the pan" and quit trains soon after introduction. Marx continued with these cars till about 1955 but by then was moving to plastic. I rarely use the term "rare" with Marx as his business philosophy was "low price / volume sales" but as its nearly 70 years old and in reasonably good shape its certainly unusual. Thanks again for your comment.
Best Wishes
Don