I wouldn't think it would be a problem to post a screenshot of something you altered with or without the author's permission, but others feel differently, and I don't know what the specific laws are.
WCL, and others: I found this nugget in May 09 Model Railroader Magazine, as a side article to "Diesel Era Grain Operations". I have copied it from the article titled "Moving Grain in Boxcars". It's no great leap to understand how the practice was also used for wood chips!
If you model the first half of the 20th century, your elevator tracks won't be filled with covered hoppers. Instead, strings of boxcars will be parked here waiting to be filled with grain.
To keep the grain inside the car, wood or paper grain doors (the latter first appeared in 1948)
were nailed inside the door opening. This was known as "coopering". About 3/4 of the opening
was covered.
Prior to loading the car, the sliding door opposite the loading chute was closed. Then an elevator employee would stand outside the car, directing the chute until the car was loaded. Since not all grains are alike (wheat and corn, for example, are heavier than oats), the boxcars had load lines marked on the inside so the car wouldn't be filled beyond it's load limit.
Though loading the boxcars was fairly easy, getting the grain out was difficult and time consuming. When the car arrived at it's destination, the doors were pushed in (paper doors were torn open) and the grain would spill out into a receiving pit. Some larger elevators, including one owned by the Great Northern Ry. in Superior, Wis., had car dumpers that tipped the cars sideways and end to end. However, these weren't 100% effective. In both cases, elevator employees would have to use shovels or vacuum systems to clean out any grain still in the car.
In the 1960s, railroads began using special grain-loading boxcars. These cars had conventional plug doors with hatches near the top for loading and inspecting grain. Though these cars didn't require coopering, they still had the same drawback (difficult to unload) as conventional boxcars.
Boxcars were regularly used in grain service through the 1970s. On the Burlington Northern and Chicago and North Western, box cars were used even into the 1980s on branchlines where 100-ton covered hoppers were restricted because of poor rail conditions. In Canada, 40-foot boxcars were used on branch lines in the prairie provinces until 1996. - Cody Grivno