Hi, I would like to jump in here with some thoughts.
Bill Welch, an historian as much as a modeler, has questions identifying doors from the Youngstown door co. produced during our era of interest. He is not alone.
As in most other components used on steam era freight cars, door manufacturers simply offered product for applications by width/height. Small changes were often running changes when an improvement made its way into production. Even so,there were three very distinct styles of Youngstown doors made in our favorite era.
Authors, modelers and tool makers need to be able communicate the ID of the various doors to clear confusion. Similar to how modelers issued "phases" for EMD's F unit line of locomotives (Something EMD never did) to communicate and make sense of the various deviations over time, Youngstown doors have had modeler's IDs applied. Unfortunately, standards have not yet been agreed upon; so confusion is not avoided; such as Bill Welch's.
Simple code initials (such as Y2-A) work well for large tables (such as Ed Hawkins' great freight car summaries) where the reader can refer to the bottom of the table to a more verbose description. However, simply identifying a door in an article as a "Y2-A" isn't helpful to 99% of the readers outside of these tables. We need a nomenclature which is intuitive, brief, understandable and made a standard.
I propose following Dan Hall's method to id'ing Youngstown doors. Dan makes various Youngstown and superior doors for HO in his Southwest Scale Models' line.
Pre-war Youngstown doors were typically made of 3 (sometimes 4) pressed steel sheets riveted together to make the size sufficient to cover the door openings. The riveted joints were in the flat area of the sheet recessed towards the inside of the car. Each section has ribs stamped into it which forms rectangular panels which are very easily spotted and counted from even lesser quality photos.
A typical Youngstown door on a 1937 AAR box will have , counting from top-to-bottom a 5/6/5 pattern of panels. To accommodate differing heights, the door maker simply uses taller sheets for the top and bottom sheets so the adjustment of height is made in the joint area. For a pre-war Youngstown door, this feature is noticable and should be addressed. At a minimum, the riveted joint sections produce a panel which is nearly identical in dimensions as the 5/6/5 panels themselves. Being the shortest variant, I call these -S (for short). A taller door will have the joint panel somewhat taller than the standard panels, so I label these as -M (for medium). The tallest Youngstown door's joint panels are almost twice the height of the regular panels. If the door needs to be even taller for its application, the maker will simply add more panels (though in the pre-war time, doors would more likely have LESS panels for inside height cars lower than the AAR '37). The taller joint panel doors would have a -T ( for tall) to cover the door openings for a 10'6" IH car <pre-war 5/6/5-T>.
A 1937 AAR pre-war Youngstown 5/6/5-S (The S need not be attached as it is obvious)
A Youngstown 5/6/5-T door on a single sheathed box car
Examples: A '37 AAR boxcar would typically be 6' pre-war 5/6/5-S Youngstown Steel door. Simplified to <Pre-war 5/6/5 YSD> (the "S" could be left off as it could be inferred that the most common variant is the 'S'. A 10'6" IH AAR box car would have a taller door opening and the most common door for these cars was the <pre-war 5/6/5-T>. Fewer doors were built with the 'M' spacing.
1947 saw the introduction of the improved Youngstown door. Lessons learned from more than a decade of production of the pre-war versions allowed a redesign which was very noticeable. Changes to the perimeter frame area strengthened the door. To accommodate these changes, the joint section was substantially changed. Now it was more like a crimped joint and no longer would the joint area be where slight variances in height would be achieved. From then on the height differences would be totally from the addition or subtraction of panels, and to a lesser degree, variations in the perimeter frame.
Most AAR box cars built at this time were to the 10'6" inside height. For about one year, this new door had a panel count of 6/6/5. After this brief period, the doors were made with 5/6/6 panels, and continued for decades with little changes. Since the joint sections were un-changing, no 'S' 'M' or 'T' appellations were necessary. A typical door for a 10'6" car would be <5/6/6 Improved YSD>.
Single year (1946/47) offering of the "upside down" 6/6/5 Improved Youngstown door
A 5/6/6 Improved Youngstown steel door (Late 1947 and on)
Youngstown steel improved doors for 10'0" nominal height cars were common in two variations; a 4/6/6 and a 5/6/5
