Possession Limit Board
定义: A physical sign placed on the track to mark the boundary of a possession, warning any approaching train that the line ahead is blocked.
示例: The possession limit board was placed 400 metres from the worksite
定义: A physical sign placed on the track to mark the boundary of a possession, warning any approaching train that the line ahead is blocked.
示例: The possession limit board was placed 400 metres from the worksite