The plaintiff must, within thirty (30) days after final judgment, pay the sum of money assessed, but may, at the time of or before payment, elect to build the fences and cattle guards, and, if he so elect, shall execute to the defendant a bond, with sureties to be approved by the court, in double the assessed cost of the same, to build such fences and cattle guards within eight (8) months from the time the railroad is built on the land taken, and, if such bond is given, need not pay the cost of such fences and cattle guards. In an action on such bond the plaintiff may recover reasonable attorney’s fees.