On Dec 8, 2006, at 8:55 AM, Gatwood, Elden J SAD wrote:

My question is till, what about the vast numbers of later '44 AAR
types, that
did not make it onto Ed Hawkins' list. What were their numbers?

Elden,
I have compiled rosters of various 10'-6" IH postwar AAR box cars built
from 1948 and later with various versions of Improved Dreadnaught Ends
(IDE) used after the 4/4 arrangement. Some of the rosters have been
published in Railmodel Journal, including cars with so-called "dartnot"
ends (see Oct. 1990 RMJ) and the late-version R+3/4 IDE used beginning
in 1955. I have also compiled a roster of AAR box cars with the earlier
R+3/4 IDE (i.e., main corrugations having the rolling pin appearance),
however, I have yet to publish it. I'm considering an article on this
subject in Railway Prototype Cyclopedia. If not there, perhaps in
Railmodel Journal. There were a few other AAR-style box cars using
other proprietary ends, such as the AC&F 4/4 ends used on several
series of Reading, M-K-T, and DT&I box cars.

Roads having the early-version R+3/4 IDE include AA, ACL, BAR (plug
door insulated box cars), C&EI, C&S, C&WC, CB&Q, CNJ, CP, DT&I, Erie,
FW&D, GM&O, GN, GTW, IC, I-GN, ITC, LV, MP, NH (plug doors), NJI&I, NP,
NYC, P&LE, PRR, RDG, Soo Line, SP&S, StLB&M, T&P, UP, WAB, and WM. Some
of these cars had overhanging roofs. Quite a few models representing
these prototype cars have been offered by Branchline Trains. My count
of prototype AAR box cars having early-version R+3/4 IDE is about
48,000 and the cars were built from 1948 to 1954. In addition to the
above list, there were also the unique "box cars" for carrying
cryogenic gases (see RP CYC Vol. 14), although these cars all had small
doors in the ends, roof hatches, and were classified as tank cars.
Regards,
Ed Hawkins