Bob Chaparro <thecitrusbelt@...>
I give my thanks to Gene Green and Richard Hendrickson for their help on this question. Just about all that I have found since posting the question is consistent with their comments.
I did find that TRAINS Magazine did an article ("The Perilous Push Pole") from March 1993 on this subject. The article noted at one time there was an AAR standard for the pockets themselves. The TRAINS article also quotes an ICC official who states, "If the push pole was officially outlawed I have no record of that fact…"
That said, the August 1993 issue of TRAINS reported that in October 1992 a Grand Trunk Western brakeman was killed while allegedly poling a car in the railroad's Detroit Rouge Yard. The GTW had banned the practice before this incident but sometimes employees take shortcuts. The TRAINS March 1993 article on the push pole has a photo of a GM&O GP-38AC with poling pockets and a GP-18 with poling pockets. The GP-18 belonged to…GTW!