Jimmy,
Thank you very much for the info. I do not know if this pertains, but during the time I worked for the Milwaukee Rd at Bensenville, Il. I worked as a phone director, sort of a mini dispatcher. I authorized and kept track of all movements from B'ville to Tower A-5 and Western Avenue on #'s 3 & 4 MT among other things. I also got involved with #'s 1 & 2 if a problem developed or a switch run was working off of #1 MT.
I digressed. I was told that the RR had to retain all dispatcher sheets for 7 years. That could be part of the reason you could not obtain some of the later sheets. Does not explain back to the '60's however.
Ron