A
bridge line or
bridge route is a
rail carrier tasked primarily with moving
traffic from one major carrier to another (hence the "
bridge" moniker). Bridge lines often were located between two major
cities, connecting rail carriers that served those cities and interchanging their cars. As
railroads have continued to evolve and large Class I railroads have sought to keep cars on line (as well as collect the revenues for the tonnage moved over their own route miles), most bridge lines are now gone.