49 C.F.R. § 232.3 – Applicability.

(a) Except as provided in paragraphs (b) and (c) of this section, this part applies to all railroads that operate freight or other non-passenger train service on standard gage track which is part of the general railroad system of transportation. This includes the operation of circus trains and private cars when hauled on such railroads.
(b) Subpart E of this part, “End-of-Train Devices,” applies to all trains operating on track which is part of the general railroad system of transportation unless specifically excepted in that subpart.
(c) Except as provided in § 232.1(d) and paragraph (b) of this section, this part does not apply to:
1. (1) A railroad that operates only on track inside an installation that is not part of the general railroad system of transportation.
2. (2) Intercity or commuter passenger train operations on standard gage track which is part of the general railroad system of transportation;
3. (3) Commuter or other short-haul rail passenger train operations in a metropolitan or suburban area (as described by 49 U.S.C. 20102(1)), including public authorities operating passenger train service;
4. (4) Rapid transit operations in an urban area that are not connected with the general railroad system of transportation;
5. (5) Tourist, scenic, historic, or excursion operations, whether on or off the general railroad system;
6. (6) Freight and other non-passenger trains of four-wheel coal cars;
7. (7) Freight and other non-passenger trains of eight-wheel standard logging cars if the height of each car from the top of the rail to the center of the coupling is not more than 25 inches; or
8. (8) A locomotive used in hauling a train referred to in paragraph (c)(7) of this subsection when the locomotive and cars of the train are used only to transport logs.
(d) The provisions formerly contained in Interstate Commerce Commission Order 13528, of May 30, 1945, as amended, now revoked, are codified in this paragraph. This part is not applicable to the following equipment:
1. (1) Scale test weight cars.
2. (2) Locomotive cranes, steam shovels, pile drivers, and machines of similar construction, and maintenance machines built prior to September 21, 1945.
3. (3) Export, industrial, and other cars not owned by a railroad which are not to be used in service, except for movement as shipments on their own wheels to given destinations. Such cars shall be properly identified by a card attached to each side of the car, signed by the shipper, stating that such movement is being made under the authority of this paragraph.
4. (4) Industrial and other than railroad-owned cars which are not to be used in service except for movement within the limits of a single switching district (i.e., within the limits of an industrial facility).
5. (5) Narrow-gage cars.
6. (6) Cars used exclusively in switching operations and not used in train movements within the meaning of the Federal safety appliance laws (49 U.S.C. 20301-20306).