Haw. Rev. Stat. § 273-13: Bylaws, regulations.

The corporation may from time to time make bylaws and regulations for the management and control of the railway, and for regulating the traffic thereon; and the bylaws and regulations on being approved by the governor, shall have the force of law. The corporation shall, at all times, cause a copy of the bylaws and regulations to be posted and exhibited at the principal stations on the line of railway.