"Speculation, yes, but I tend to doubt that by this point in time the railroads specified the details of the vendor supplied products... they would order what the vendor offered. Anything else would be a 'special' with the higher cost that would entail. That's not saying Youngstown didn't decide to put the larger panel on the bottom for just this reason, either on their own or at the prompting of one or more customers, but it appears that once the change was made it became the new 'standard'. Does anyone know if the bottom panel actually was heavier gauge steel? I don't have easy access to any YSDCo. drawings."
1937 and 1941 AAR drawings for the 6 foot wide (3 panel) Youngstown doors show 13 gauge steel for the panels. The 1945 revision shows that the bottom panel was 13 gauge steel and the center and top panels were 14 gauge steel. The 1948 revision shows that the bottom, center and top panels were all 14 gauge steel.
The 1941 7 foot and 8 foot wide doors (4 panel) were 13 gauge with the 1945 and 1948 revisions being the same as above.
