Colo. Rev. Stat. § 40-21-101
Every railroad company chartered by this state shall keep and maintain permanently its general offices within the state of Colorado at the place named in its charter for the location of its general offices; and, if no certain place is named in its charter where its general offices shall be located and maintained, said railroad company shall keep and maintain its general offices at the place within this state where it contracts or agrees for a valuable consideration to locate its general offices; and, if said railroad company has not contracted or agreed for a valuable consideration to maintain its general offices at any certain place within this state, such general offices shall be located and maintained at such place on its line in this state as said railroad company may designate.
C.R.S. § 40-21-101