Colo. Rev. Stat. § 43-1-1304
Whenever an owner of a rail line or railroad right-of-way intends to dispose of such property, the owner shall notify the executive director of such intention in writing. The executive director shall, within thirty days after the receipt of such notice, inform all departments of the state of Colorado, the metropolitan or regional transportation authorities, and cities, counties, and towns where the property or a portion thereof is located of the owner's intention to dispose of the rail line or right-of-way. The state and any metropolitan or regional transportation authority, cities, counties, and towns affected by the intended disposal shall have ninety days after the announcement of the intended disposal in which to contact the owner in writing to express an interest in acquiring the property or preserving rail service. If the owner receives written notice within the ninety-day period after the announcement of the intended disposal, the owner shall provide such public entities the opportunity to purchase the rail line or right-of-way.
C.R.S. § 43-1-1304