Ed Morlok was very interested in this firm. As best we could tell their production, very limited, included the following models:
4-4-2, Reading P-7, sand cast boiler
4-6-2, CNJ, sand cast boiler
This advertisement is from the January, 1936 issue of The Model Railroader. The residence of owner Howard A. LeVan, Jr., was the Halderman House, which was the home of the Governor of Pennsylvania from 1823-1829 and was later maintained by the PRR as the residence of its General Superintendent from 1896-1926.
While Thuillgrim did make a few parts and certainly at least a sample of their 4-6-4, The OO Gauge Model Co. 0-4-0 is the first locomotive actually produced in OO with examples known to exist today. Who knows when the next one will turn up for sale; it is an extremely rare model to keep your eyes peeled for.
First is this view of the boiler and cab. Note the size of this compact model and the card with it.
One final thing to mention as I have a bit more space, I have always been fascinated by the name choice of this company. "The OO Gauge Model Company." Sounds big! They were in early, had some plans for sure, and their models are among the rarest ever produced in American OO.
UPDATE II: And the model featured in the third photo in this article is I think pretty likely an example of their 4-6-2 model.