Abstract
Under the speed-up on electric railways, overhead catenary systems on narrow-gauge lines have been improved with an increase of messenger wire tension. However, contact loss ratio of pantograph is comparatively high under the heavy simple catenary or feeder messenger wire type overhead catenary. These catenary has higher tension of messenger wire. In order to investigate into the causes and to work out effective improvement methods, laboratory and field tests have been carried out. From the results thereof, it is confirmed that contact force fluctuation comes under the influence of wave reflection factor at hanger, and a hanger which has spring mechanism is found effective to improve it. It is expected that rubber damping hanger or friction damping hanger contributes to reducing the contact loss of pantograph and the wear of contact wire.