trainreset：有许多列车需要开车出站的作用。

代码说明：

TrainReset:there are many trains need to drive out of the station .In terms of their numbers from small to large.There are only three railways used to place the trains ,and also need the same order.-TrainReset : there are many trains need to drive out of the sta tion. In terms of their numbers from small to deviation ge.There are only three railways used to place t he trains, and also need the same order.