What you need
To repair a fence you will need a section of top rail with one open end and one crippled end. You will also need a hacksaw, file and pliers and a helper.
Fixing The Fence
Start by removing the wire ties that hold the fence fabric to the top rail, then rest the new rail on top of the damaged rail and have your helper hold it in place while you mark a cutting line on the old rail. Mark a cut on the other end of the new rail where it meets a joint. Cut the damaged rail at the cutting line then slide it off the joint and toss it. The ncut the excess of the top rail to mate with the existing joint. Create some maneuvering room by unbolting the top rail and sliding it away from the damaged area. Install the new rail onto the old rail and reconnect the corner post.