In March of 1940 we find in The Model Railroader this advertisement for a new line of OO gauge body kits. They are by Yardmaster Lines and distributed by The Spot Hobby Shops in Baltimore.
the Morlok auction a few years ago (I bid online on them but did not win) so I believe that these were actually produced.
The ad itself states the details of the line pretty well (click on the ad for a bigger view). Without seeing an example of these cars it is difficult to say if they recycled parts of some other line or were an absolutely unique product.
The only other published reference I have found from the period is in the classified advertising in the November, 1940 issue of The Model Railroader, where we read that there is a “40% Discount Sale on Yardmaster OO body kits. Originally $1, now 60c. Individual sides and ends, 15c per pair.” They were still for sale from the same source, Spot Hobby Shops.
With that I throw this out to readers—anyone have an example of a Yardmaster Lines OO kit? Someone must! I would love to hear from you with a photo or two.
UPDATE I: Is the third car in this article built from a Yardmaster kit?