(a) Except as provided in paragraph (b) of this section, this part includes requirements for the following persons. Specific sections in this part provide detailed requirements. (1) Each freight railroad carrier that operates rolling equipment on track that is part of the general railroad system of transportation.(2) Each rail hazardous materials shipper.(3) Each rail hazardous materials receiver located within an HTUA.(4) Each freight railroad carrier serving as a host railroad to a freight railroad operation described in paragraph (a)(1) of this section or a passenger operation described in § 1582.1 of this subchapter.(5) Each owner/operator of private rail cars, including business/office cars and circus trains, on or connected to the general railroad system of transportation.(b) This part does not apply to a freight railroad carrier that operates rolling equipment only on track inside an installation that is not part of the general railroad system of transportation.