To keep safety of rolling stock running on curve section, it is very important to reduce wheel load variations of bogie truck on the track cant run-off section. In this study, some new devices of primary and secondly suspensions have been developed, then field tests with the truck equipped new devices are carried out. The field test results show the reduction of wheel load variation by 20% from the conventional condition when the rolling stock run at low speed. Also to keep safety even under the air spring puncture condition, new air spring with stopper has been developed, and the wheel load variation under the puncture condition is lower than the maximum load variation for safety.
