Abstract: The invention involves a suspended trolley line, particularly an electric monorail line with at least one undercarriage movable along running rails and with a running wheel that may be driven along the rail. At least two frictional wheels are spaced from each other and positioned on the running wheel. The frictional wheels are guided on the undercarriage by a connecting element and are braced against each other by a spring element, such that the frictional wheels additionally contact the supplemental rail and impinge upon the running wheel with pressure when in an operating position. The supplemental rail is located at least partially parallel to the running rail and spaced therefrom. The driven undercarriage is simple in its construction and has improved traction characteristics and therefore is particularly capable of being used in ascending and descending sections of the trolley line. The frictional wheels, the connecting element and the spring element form an assembly unit lying on the running wheel.