Adding a rotor blade (it had five on the main rotor and four on the tail) and using a modified exhaust system were among them.
增加一个桨叶(主桨有5个叶片，尾桨有4个)，并使用了改进的排气系统。
2
The main cooperation was on the onboard ATP system, which Hollysys documents describe as components in the nose andtail of trains that act as its' last line of defense in safety.