I'll not post the photo due to copyright, but the original is available through the National Archives or you can get a copy of Squadron Signal's PT Boats in Action. On page 48 of that publication is a picture of a partially completed 78' Higgens boat, PT 201 on SP 79571, a 52' flat car. This shot may have been an intra-plant transfer at Higgins Louisianna yard prior to launching, or it may have been prior to shipment to a port for overseas carriage on board a larger ship. Absent confirmation of the former, I will take modeler's license and assume the latter for the North Bay Lines. I have determined from the Official Railway Equipment Register that the car is a 52' flat. Now to find the class and an HO model of the car. The boat in this case is relatively easy. Revell made a 1:96 scale kit of PT 212,the same class. Not very detailed, but OK to match the photo and as a main line car load. And I just happen to still have the assembled kit I built as a pre-teen in the 60's. Talk about serendipity! I will update this in a future post.