I have seen pictures of lifeboats and smaller navy personnel boats being shipped by rail during World War Two, but I cannot recall any photos of a PT boat traveling by rail. The PT boats were 77 to 80 feet in length with a beam that vastly exceeded railroad clearances. Elco, Higgins, and Huckins, the three wartime PT builders were all located on bays or waterways, and for long distance shipment the PT boats generally ran under their own power to a port and then were loaded as deck loads on tankers. I think I remember seeing pictures of John Kennedy's PT109 in a government photo survey taken while the boat was being loaded on a tanker months before his famous encounter with a Japanese Destroyer.
Some of the wartime transportation solutions are absolutely fascinating, like the travels of fleet submarines built in Manitowoc, which went through Chicago to Joliet, Illinois under their own power and were then loaded onto a floating drydock so a tug could take them down the river to New Orleans, where they were floated and proceeded again under their own power to the Pacific. There was an article about this operation years ago in Naval Institute Proceedings.
"We Repair No Locomotive Before Its Time"
In 24+ years on the job, I have never seen a boat on a railcar, anywhere, at anytime. (excepting some marinas use a cradle car, on rails, for hoisting cars into and out of the water. in no way connected to a railroad, however) Regards 
