Hmmm, not sure why the IC would short-haul itself by handing off to MILW at Dubuque. The IC had good service to the Twin Cities by handing off to the M&StL at Albert Lea (also with plenty of SB meat reefers).
As always, remember that the railroad did NOT control routing, shippers did. If there was some advantage in time or rate to hand off at Dubuque, the shipper could so specify. IC not liking it was not a factor.
Tony Thompson Editor, Signature Press, Berkeley, CA