The Magnolia Branch was constructed in 1898 in order to reach the town of Magnolia (about 650 population). The Magnolia Coal Company advanced to the Baltimore & Ohio Railroad $35,000 to aid in its construction; in return, the B&O served their coal mines along the short 5-mile route. The line branched from the B&O mainline at Sandyville, OH, and ran eastward to Magnolia, where it also served a flour mill.
The line did see passenger service via a mixed train that ran daily between Sandyville and Magnolia. This service lasted until April of 1918.
Shortly after this branch was in operation, the Pennsylvania Railroad built their own mainline directly through Magnolia, which was not large enough to support the operation of two large railroad companies. Due to dwindling coal returns from mines along the route, and the decreasing commerce from Magnolia as it shifted to the new PRR mainline, the B&O decided to abandoned the Magnolia Branch in 1922.