Colo. Rev. Stat. § 40-22-101
It is lawful for any railroad company or corporation, organized or existing under the laws of this state, and whose line or road is made or is in the process of construction to the boundary line of the state or to any point either in or out of the state, under authority of its laws, to merge and consolidate its capital stock, franchises, and property into and with the capital stock, franchises, and property of any other railroad company or corporation organized and existing under the laws of any adjoining state whenever the two or more railroads of the companies or corporations so to be consolidated form a continuous line of railroad with each other or by means of any intervening railroad; and roads running to the bank of a river which is not bridged shall be held to be continuous. Nothing in this article shall be taken to authorize the consolidation of any company or corporation of this state with that of any other state, unless the laws of such other state authorize such consolidation; but parallel or competing lines of railroad shall not be consolidated.
C.R.S. § 40-22-101