bar barrier crossing cutout fence isolated rail railroad railway Railway crossing roadsign roadsigns sign signs warning autumn Forrest HDR track tracks train advice alert announcement appropriate-behavior appropriate-behaviour be-careful beware black care careful cars caution communicating communication concern danger dangerous directions informing listen Look looking lookout observant rails railway-crossing red risk risks road safety trains warning-sign watch watch-out white bridge canal channel cross river steel water blue cattle cattlegrid gate grid Nyberg path sky summer change changing crossroad direction paths railwaytracks train. tracks wood broken lamp old railways rusty stop weird cantilever dark Edinburgh Forth girder scotland sea