 The 3.5 mile, single-track line of the Catonsville Short Line Rail Road Company began operating on November 10, 1884.It provided passenger and freight service from Baltimore & Potomac Railroad at St. Agnes station (near St. Agnes Hospital to Mellor Avenue in Catonsville.Passenger service on the Catonsville Short Line became unprofitable when the electric trolley began service along Frederick Road in 1897 and was discontinued by the railroad in 1898.