Granted, you can't keep running with loose parts rattling around in the cylinder, but it was pretty common to run an engine in on one side after a breakdown in the cylinder or valve gear on the other side. Remove the broken parts, disconnect and center the valve on the broken side, and be careful not to stop on dead center on the working side. In "One Man's Locomotives", there is an account of a Santa Fe 4-8-4 being run to the distant shops on one side, pulling a tonnage train (double headed with another engine to keep from getting stuck). I'm sure that happened on the RGS on more than one occasion.