49 CFR 239.3: Application.

(a) Except as provided in paragraph (b) of this section, this part applies to all:

(1) Railroads that operate intercity or commuter passenger train service on standard gage track which is part of the general railroad system of transportation;

(2) Railroads that provide commuter or other short-haul rail passenger train service in a metropolitan or suburban area (as described by 49 U.S.C. 20102(1)), including public authorities operating passenger train service; and

(3) Passenger or freight railroads hosting the operation of passenger train service described in paragraph (a)(1) or (a)(2) of this section.

(b) This part does not apply to:

(1) Rapid transit operations in an urban area that are not connected with the general railroad system of transportation;

(2) Operation of private cars, including business/office cars and circus trains; or

(3) Tourist, scenic, historic, or excursion operations, whether on or off the general railroad system.