The single set of tracks outside the museum's fence follows the original right-of-way of the Baltimore & Ohio Railroad, a route in continuous use since 1830 and now owned by CSX Transportation. A second set of tracks was added in 1859 between Ellicott City and Baltimore, but flooding, erosion, and decreased operations later reduced the line to a single track. The tracks leading into the east end of the main depot depict the layout used between 1833 and 1863, while the second set of tracks on the wooden bridge depicts a partially restored turntable used from 1863 into the late 1890s. The Baltimore & Ohio built the turntable to turn local freight and passenger trains running between Baltimore and Ellicott's Mills, the town's original name until 1867. The 1863 turntable had a center pin resting on a pivot mechanism and stone support pillar, with the bridge connected to four wheels running on a circular rail around the pit's outer edge, allowing one person or animal to rotate a balanced locomotive. It was 50 feet in diameter, had a pit seven and a half feet deep, and could hold about 30 tons. Part of the Ellicott City center balance turntable was excavated in 1999, while the rest remains beneath tracks still used by CSX. A similar turntable appeared in the December 1853 issue of The American Railroad Journal. In addition to freight cars and small passenger cars, the Ellicott City turntable could turn an engine and tender the size of the William Galloway. A 1927 replica of the Lafayette, built for the centennial celebration of the founding of the Baltimore & Ohio called The Fair of The Iron Horse, was later used at fairs including the 1933 Chicago World's Fair and 1939 New York World's Fair and in some films. For a short time, that replica was renamed William Galloway to honor a noted early Baltimore & Ohio engineer, and the fully functioning replica is now displayed at the Baltimore & Ohio Railroad Museum in Baltimore.
