I recently took possession of two girder bridges made by this company and have not been able to locate any information about the firm (see photos). The TCA Western Division website has a pretty comprehensive list of manufacturers, but unfortunately this company is not included there.
The bridge is similar to Lionel’s 314, with the die cast sides. However this model is one half inch shorter in both length and width from Lionel’s, at only 10” x 4”.
Love these great mysteries and hope some of our more knowledgeable colleagues can share some history.