Mont. Code § 70-30-307
In a proceeding for condemnation for a railroad, the condemnor shall within 30 days after final judgment pay the sum of money assessed but may at the time of or before the payment elect to build any required fences and cattle guards. A condemnor who elects to build the required fences and cattle guards shall execute to the condemnee a bond with sureties to be approved by the court, in double the assessed cost of the fences and cattle guards, conditioned upon building the fences and cattle guards within 8 months from the time the railroad is built on the land taken. If the bond is given, the condemnor is not required to pay the cost of the fences and cattle guards. In an action on the bond, the condemnee may recover reasonable attorney fees.
§ 70-30-307, MCA