|Litchfield, Minnesota, John Vachon, September, 1939, FSA-OWI Collection, Library of Congress|
For far longer than seems plausible, the primary means to ship bulk (loose) grain was not covered hoppers, but box cars. Obviously, filling grain into cars that were loaded with the doors open required some type of accommodation to “trap” the grain and prevent it from spilling out onto the area below the car doors. What was needed was a temporary “block” that could be easily installed and removed trackside, with a minimum of tools and skill.
|Vernon, Texas, 1948, Lee Russell, photo, CB&Q Railroad, Newberry Library|
The solution was through the application of grain doors. These were pre-fabricated assemblies of wood planks that spanned to the door opening and were nailed in place, with the number appropriate to the type of grain being loaded. More dense (heavy) grains took up less space before maxing the car’s capacity; conversely, less dense grains used more of the cubic capacity of the car and required more grain doors to be used (capacity "fill" lines were stenciled on the inside lining of cars as shown in this and the photo below). The doors were stacked across the opening, edge on top of edge.
|Interior of Delaware & Hudson 1932 ARA box car|
The doors were expected to be reused and were supposed to be returned once the trip was completed. The railroads owned the doors and provided them to shippers gratis. For a fee the railroads could install the doors if desired. The doors were to be routed back to the owning railroad. They were collected and sorted by owning railroad and eventually made their way back to collection locations at interchange points. The Western Weighing and Inspection Bureau collected doors at major terminals and returned them, even calculating usage fees.
|Interior of Canadian Pacific 1932 ARA box car|
In 1948, paper grain doors were introduced by Signode. Their use was gradually adopted throughout the 1950s. In the early 1960s, box cars with small grain doors built into the larger sliding doors were introduced, a simpler and cleaner option compared to wood or paper grain doors. Also, the introduction of covered hoppers for grain transport in the 1940s and 1950s initiated the overall decline of box cars for grain transport.
Sunshine Models provided a set of resin grain doors as a handout to attendees of one of the Naperville meets. While these are nice, scratchbuilding a set would also be a simple proposition. There is a drawing of a Northern Pacific grain door on page 57 of The Model Railroader’s Guide to Grain by Jeff Wilson from Kalmbach. In addition, much of the material presented here is drawn from that resource. It is highly recommended as are the other titles in that series