[交] substituting service
... sub-carriage 分运 substituting service 顶班 suburb passenger flow 市郊客流 ...
to substitute for
... 当班 to work one's shift 顶班 to take over sb else's job; to substitute for 短训班 short training course ...
relay
... man vt.给…配备职员 relay n.顶班;接力竞走 blow vi.&vt.爆炸;爆裂 ...