Abstract
AC Train is the first JR East commuter train to adopt the articulated structure. Two types bolster-less articulated trucks (two air springs type and four air springs type) were developed for AC Train. The results of a running test shows that good running safety is obtained in both articulated trucks. Furthermore, it was confirmed that the four air springs type can improve the wheel unloading on running a transition curve. Therefore, it is considered that this is effective for improvement of the safety to the wheelclimb derailment.
