A few musings on this subject while I finish my morning coffee...

I did some rough (very) compilations based on roster data provided by Ed Hawkins for our research (some of which is available on Ted's site I believe) and came up with the following data. these numbers are rough and include 10 and 12 panel cars as well as riveted and welded construction, but since door size is the issue here I didn't break it down any further

There were 148,199 (!) total 40' boxcars built between 1945 and 1960.

108,736 (~73%) of these were 6' door cars sold to 48 railroads between 1945 and 1958.

10,576 (~7%) of these were 7' door cars sold to 14 railroads between 1946 and 1956.

26,822 (~18%) of these were 8' door cars sold to 33 railroads between 1946 and 1960.

2,065 (less than 2%) of these were 9' door cars sold to 6 railroads between 1956 and 1961.

Other observations:

All three common door openings (the 9' was an oddity) were INTRODUCED at roughly the same time (1945-46), but as a rule, the 6' door cars are built earlier, 8' door cars later.

Only the Erie owned (new) cars with all three door openings.

A few roads (ATSF, CB&Q and NYC for example) stuck with all one size door (6' in this case). Most had 6' and then 8' door cars later, except of course the PRR that had 7' and then 8'. Some roads (Southern as early as 1947) went with ONLY 8' door cars (why???).

So, what does this mean as a modeler? Let's say you need 25 of these cars total for your fleet - we all need more than that, right :>) , you model a time period after about 1955 and are basing your fleet on the national average then you will need 18 x 6' door cars, 2 x 7' door cars, and 5 x 8' door cars. Of course, if you model the Southern you will need a couple more 8' door cars, the PRR guys will need more 7' and 8' door cars.

Hope somebody finds this useful. Guess I'd better get back to making more of these things!

Bill Schneider