I am trying to learn more about the Baltimore and Ohio. I have a book called Baltimore And Ohio Railroad In The Potomac Valley, by Martin J. McGuirk. It is part of Kalmbach publishing's Classic Trains: The Golden Years Of Railroading series. On three place, pages 11,12, and 46 a map is shown where Sand Patch is clearly labeled as being between Harpers Ferry and Cumberland, MD. However, maps on the internet place the grade on the opposite side of the line between Cumberland, MD, and Connellsville, PA. So, did Kalmbach make a typographical error three times?
One the map you have displayed Sand Patch Grade is actually between Meyersdale and Cumberland. The territory between Cumberland and Brunswick (where the grade indication is displayed) is the gentlest grades on CSX's Baltimore Division as it nominally follows the water level grade of the Potomac River.
Kalmbach is wrong!