Probably, but only via anecdotal observation. When I came around the RR in 1970 quite a few box cars would have routing instruction stenciled by the doors... " when empty return via reverse route." There was a huge imbalance in reefer loads coming out of the west CA,OR, WA. The PC would send probably 65% of the inbound reefers waybilled to the east coast, back empty. The other 35% would back haul things like cigarettes, beer and LTL from outfits like ACME FAST FRIEGHT, LIFSCHUTZ, Clipper carloading, Western carloading and Chicago Shippers east coast branches etc. The reefers would be handled MTY or load in hotshot trains like Harsimus cove - Chicago PR-9 or Jersey City- St Louis PR-7 and authorized to operate 60 mph. I recall they instituted a 72 car limit on piggyback trains in and out of North Jersey, that operated via the old PRR, due to the derailments longer trains were experiencing while being pushed over the mountains out of Altoona PA. They started using empty deadheading westbound reefers, coupled ahead of the cabin car.That reduced jackknifing caused derailments and got the reefers back out west faster, when Junes' western harvest campaign kicked in full blast, and the WP SP And UP had all kinds of eastbound produce traffic ready to load and no reefers.
Most of the rates given to western produce shippers would fold in the cost incurred by DH-ing the MTY cars back off the east coast. A few produce hauling truckers I knew would position themselves out in California about the second week in June when the RR reefer shortage kicked in and land 6000 dollar loads of strawberries destined for east coast markets. This was back in the 1970's, guys called the strawberry loads, mortgage lifters.
Re; Aroostook potato traffic. The three RR's marketing groups would have to identify receivers down south who had the volume of business to handle unit containers or railroad reefers, then work backwards through all three carriers for scheduling then get the Aroostook farmers on board for the logistics end of things. To me it seems the RR's just don't have the interest or zeal required to put a complex and possibly low revenue deal like this together. I foresee maybe two round trips a month for said assigned equipment and from what I read here,PAR's service is non existent. So the trucker's have the business and are making a small profit, the farmers are getting excellent service and there it stands.