When dealing with trees and poles along the railway, make sure you know your vines! There's fox grape, bitter sweet, Virginia creeper and then there's poison ivy. This photo shows an exceptionally old vine that is literally covered with hair. The hairs are many tiny rootlets that allow this vine to climb just about anything. The hair/rootlets are the key identifier of this vine when no leaves are present, if the vine you see is hairy looking, leave it be!