A Study on the Contribution of Exterior Devices to Running Resistance in High-Speed Trains

The contribution of exterior devices such as bogie fairings and pantographs to running resistance was estimated on the basis of coasting tests at up to 350 km/h with the help of the Korean Next Generation High speed train (HEMU-430X). In order to assess the reduction of air resistance by nose car`s bogie fairing, coasting tests were conducted with a removable bogie fairing at various speed ranges. And, the contribution of the pantograph to air resistance was also estimated with coasting tests that include the pantograph`s rising and descent modes. The linear regression method was used to examine decelerations from time-velocity data and the equation of resistance to motion is proposed from the deceleration data. From the aerodynamic term of the equation of resistance to motion, the contribution to air resistance by nose car`s bogie fairing and pantograph was estimated. The results show that the air resistance was reduced by about 3.8% by the nose car`s bogie fairing. And, the 3.9% increase of air resistance by the pantograph (open knee mode) has been found.