In a message dated 9/1/2008 3:31:33 PM Central Daylight Time,
stevelucas3@... writes:

Likely you are aware that NMRA data sheet D9p has a short write-up on
MCB/AAR coupler contours and couplers, including mention of the MCB
type D, given in the data sheet as being designed in 1904, made AAR
standard in 1918, and allowed for use in new construction until the
Type E was approved as AAR standard in 1932.

The Type D coupler was adopted as "standard" by the MCBA in 1916. The
modified contour (No. 10) with a 6" x 8" shank Type D was adopted as "standard" in
1918. The Type E coupler was presented to the ARA's membership for adoption
as "standard" (via letter ballot) in 1931. The ballot passed and the Type E
replaced the Type D effective March 1, 1932.

The Type E was required (in interchange) on all cars built new on or after
August 1, 1933 and on all cars rebuilt on or after August 1, 1937. Type D
couplers cast after August 1, 1936 were prohibited on all cars (in interchange)
as of January 1, 1937.

Exceptions within the Interchange Rules covering the installation of
couplers are numerous from the mid 1930s thru the 1950s. The exceptions generally
centered on the structural limitations of early car construction which would
not allow couplers with larger shanks to be applied to cars when rebuilt or
repaired.



Does anyone have an AAR Field Manual of the Interchange Rules for 1956
that can answer if Type D couplers were legal for interchange at that
time?

The Type D was still permitted in interchange thru 1960 the final year we
focus on here.


Regards,

Guy Wilber
West Bend, WI





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