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

1. (1) Railroads that operate intercity or commuter passenger train service on the general railroad system of transportation; and
2. (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(2)), including public authorities operating passenger train service.

(b) This part does not apply to:

1. (1) Rapid transit operations in an urban area that are not connected to the general railroad system of transportation;
2. (2) Tourist, scenic, historic, or excursion operations, whether on or off the general railroad system of transportation;
3. (3) Operation of private cars, including business/office cars and circus trains; or
4. (4) Railroads that operate only on track inside an installation that is not part of the general railroad system of transportation (i.e., plant railroads, as defined in § 270.5).