Colo. Rev. Stat. § 40-24-101
Nothing in articles 20 to 33 of this title shall be construed to allow the construction of any street or other railroad or other structure or substructure for any purpose on, below, or elevated above the surface of the ground of any street or alley within the limits of any such city or town by any corporation or person without the consent of the local authorities of such city or town; but no such consent, however enacted or expressed, on any consideration whatever shall operate to relieve or protect any person or corporation constructing any such street or other railroad or structure or substructure against any claim for damages to private property which otherwise, without such consent, might be lawfully maintained against such person or corporation.
C.R.S. § 40-24-101