I was surprised to find the Conrail schedule for GREL for Sept 1982 includes a setout/pickup in Martin. Was there a crew based there at one time? There is no work at Plainwell on this schedule, perhaps there was more room at Martin than Plainwell for making a setout and the Plainwell crew retrieved the cars from Martin?

page 137: http://www.multimodalways.org/docs/railroads/companies/CR/CR%20Freight%20Schedules/CR%20Freight%20Schedule%209-1-1982.pdf