At this point, a siding, or spur, split off the mainline to serve a grain mill that once stood near the center of Columbia. The siding ran east-west behind the current location of the Metter Park tennis courts. On the way to the mill, it crossed Locust Street, Metter Avenue, Main Street, and Rapp Avenue before ending at Saint Paul Street. In the summer of 1980, a locomotive returned to the mainline after dropping off cars at the old mill.