Idaho Code § 62-203: Time for commencing and completing construction.

Every railroad corporation must, within two (2) years after filing its original articles of incorporation, begin the construction of its road, and must every year thereafter complete and put in full operation at least five (5) miles of its road, until the same is fully completed; and upon its failure so to do, for the period of one (1) year, its right to extend its road beyond the point then completed is forfeited.