Begin at the Historic Railroad Trailhead and run WEST for 2 miles before turning around and coming back the way you came. Continue onto the Historic Railroad Trail going through the 6 tunnels until you reach the turnaround at the Hoover Dam, at which point you will head back to the finish line.
Start at the Historic Railroad Trailhead and run east on the Historic Railroad Trail for 1.55 miles and then head back the same way you came.
Begin at the Historic Railroad Trailhead and run east, continue onto the Historic Railroad Trail going through the 6 tunnels until you reach the turnaround, at which point you will head back to the finish line.