CSX Transportation's Brooksville Subdivision is a railroad line in the Tampa Bay region of Florida. Today, the line runs from the Clearwater Subdivision in Sulphur Springs, Florida north to a point just north of Brooksville, a distance of 49.1 miles. Historically, the Brooksville Subdivision was owned and operated by CSX predecessor, the Seaboard Air Line Railroad. Under Seaboard ownership, the Brooksville Subdivision continued north as far as Waldo, where it intercepted the Seaboard Air Line main line.

The Clearwater Subdivision is a railroad line owned by CSX Transportation in the Tampa Bay region of Florida. The line begins just east of downtown Tampa in Gary and heads north through some of Tampa's suburban neighborhoods. In Sulphur Springs, the Clearwater Subdivision turns and runs west through Oldsmar, where it crosses Tampa Bay. It briefly shifts south running through Safety Harbor, and then heads west again to Clearwater. In Clearwater, it turns southeast, running through Largo and Pinellas Park before terminating at Fifth Avenue North in St. Petersburg near Tropicana Field. The distance from Gary to St. Petersburg along the line is 48.6 miles (78.2 km). At the line's north end it continues from the Tampa Terminal Subdivision and at its south end the track comes to an end.