(a) Except as provided in paragraph (b) of this section, this part applies to all railroads that operate steam locomotives.

(b) This part does not apply to:

(1) A railroad with track gage of less than 24 inches;

(2) A railroad that operates exclusively freight trains and does so only on track inside an installation that is not part of the general system of transportation;

(3) Rapid transit operations in an urban area that are not connected to the general system of transportation; or

(4) A railroad that operates passenger trains and does so only on track inside an installation that is insular, i.e., its operations are limited to a separate enclave in such a way that there is no reasonable expectation that the safety of the public—except a business guest, a licensee of the railroad or an affiliated entity, or a trespasser—would be affected by the operation. An operation will not be considered insular if one or more of the following exists on its line:

(i) A public highway-rail crossing that is in use;

(ii) An at-grade rail crossing that is in use;

(iii) A bridge over a public road or waters used for commercial navigation; or

(iv) A common corridor with another railroad, i.e., its operations are conducted within 30 feet of those of any other railroad.

(c) See appendix A of part 209 for a current statement of the FRA's policy on its exercise of jurisdiction.