Railroad Magazine between 1940 and 47 (mostly of locomotives), and gave me also a copy of a short article on page 56 of the September, 1940 issue on Midlin track. It has two photos, one of a worker assembling track on a machine that looks like the base of an old fashioned treadle sewing machine, and also a photo of Chemidlin himself. The text reads (the caps are original):
Fred J. Chemidlin of Scotch Plains, N.J., Grew Tired of Forcing Home Midget Track Spikes With Long-Nosed Pliers. So He Designed a New Type of Spikeless Track Assembly. Two Parallel Groves Are Cut to Gage Width in a Cross Grained Strip of Wood, and These Grooves Then Receive the Base Web of Specially Designed Rails. As the Strip is Fed into the Machine Shown in Our Lower Illustration, a Knife Cam Splits It into Tie-Width Sections Which Are Mechanically Kicked Apart to Correct Spacing. Top Photo Shows Chemidlin Assembling a Switch by Hand.The best copy I have is his Xerox version, hence the low quality of the photo but the text also describes the process pretty vividly. I have more info on Midlin track (introduced in 1939) and two photos of the product in this prior post.
UPDATE: An overview of OO gauge features in Railroad Magazine may be found here.