Steve Hile wrote:
There was some symbiotic relationship between Pennsylvania Tank Car Company and Standard Tank Car Company, with PTC being the older (1914 versus 1919). I had some discussions after publishing the UTLX book over the identification of the Ohio Cities Gas Company, International Refinery tank cars shown on page 135. It seems more likely that those cars (and the Youngstown Sheet and Tube car being discussed) were built by PTC before STC really got going.
Certainly during the 1920s STC was far bigger than PTC, and we know that zPTC bought tanks from STC to put on its own underframes. But the early high-walkway tanks we are discussing are not likely to be part of that situation. They seem to me far more likely to be PTC cars.