Good information John. Perhaps when Jimmy Blouch gets back up to speed he can research the September 1964 movements in/out of Chama to see when the last oil shipments would have gone out. Assuming that the Gramps tank car use ended with the closure of the Alamosa Oriental refinery on 10/1/1964 however Oriental had another refinery near Denver so it would have been possible I suppose to transfer the crude to standard gauge tanks at Alamosa for trans shipment to Denver via the standard gauge. I don't know this occured but oil production did continue from the Gramps field and apparently trucks were then used to transport the crude to Farmington for processing. I assume that the reason the oil traffic didn't continue via the D&RGW from Chama to Farmington could have been the lack of direct transfer facilities from the NG at Farmington to the refinery? The Conoco refinery was a shipper of refined oil products during earlier years so I don't know when tracks / facilities would have been obsoleted. Perhaps the D&RGW also wanted to avoid any further rail shipments to hasten abandonment of the NG so that may have been a factor also.
Rod