49 U.S.C. § 20102

1. (1)“Class I railroad”, “Class II railroad”, and “Class III railroad” mean railroad carriers that have annual carrier operating revenues that meet the threshold amount for Class I carriers, Class II carriers, and Class III carriers, respectively, as determined by the Surface Transportation Board under section 1201.1–1 of title 49, Code of Federal Regulations.
2. (2)“railroad”—
   1. (A)means any form of nonhighway ground transportation that runs on rails or electromagnetic guideways, including—
      1. (i)commuter or other short-haul railroad passenger service in a metropolitan or suburban area and commuter railroad service that was operated by the Consolidated Rail Corporation on January 1, 1979; and
      2. (ii)high speed ground transportation systems that connect metropolitan areas, without regard to whether those systems use new technologies not associated with traditional railroads; but
   2. (B)does not include rapid transit operations in an urban area that are not connected to the general railroad system of transportation.
3. (3)“railroad carrier” means a person providing railroad transportation, except that, upon petition by a group of commonly controlled railroad carriers that the Secretary determines is operating within the United States as a single, integrated rail system, the Secretary may by order treat the group of railroad carriers as a single railroad carrier for purposes of one or more provisions of part A, subtitle V of this title and implementing regulations and order, subject to any appropriate conditions that the Secretary may impose.
4. (4)“safety-related railroad employee” means—
   1. (A)a railroad employee who is subject to chapter 211;
   2. (B)another operating railroad employee who is not subject to chapter 211;
   3. (C)an employee who maintains the right of way of a railroad;
   4. (D)an employee of a railroad carrier who is a hazmat employee as defined in section 5102(3) of this title;
   5. (E)an employee who inspects, repairs, or maintains locomotives, passenger cars, or freight cars; and
   6. (F)any other employee of a railroad carrier who directly affects railroad safety, as determined by the Secretary.