D & RGW narrow gauge reefer plugs

The Durango Railroad Historical Society is currently restoring D &RGW 30 ft. reefer #39. The car has the ice hatch plugs still in it. Can anyone tell us what the function of the plugs were- They certainly had to be removed when the car was in transit- where did they store them? . I have found nothing in the book The Great Yellow Fleet on the function of the plugs and how they were used.
I know they were used for insulation BUT after they iced the cars and had the plugs in before getting over the road is the steps I am wondering about. After they iced the cars with the plugs in my guess is then they moved the string of cars to be loaded to the produce or meat company to load them, Just before they got on the road they must have taken the plugs out for air flow setting the dogbones the proper height for the amount of cooling they wanted. What did they do with the plugs? Leave them at the companies for return to the ice house? Why were the plugs left in our reefer when it was empty? Nothing is said about this aspect of loading ice on reefers in the Great Yellow Fleet.
Duane Danielson



Edited 1 time(s). Last edit at 05/30/2017 01:50PM by Big Steam.