A structure fixed at the termination of a Running LineA line that runs between two distinct locations, as shown in Table A of the appropriate Sectional Appendix. or SidingA line for the stabling of vehicles, loading/unloading, servicing, etc clear of the Running Lines. to arrest
slow-moving vehicles. Also known as a Stop BlockA structure fixed at the termination of a Running Line or Siding to arrest slow-moving vehicles. See also Buffer Stop..