Carrier
Carrier means a common carrier by railroad, or partly by railroad and partly by water, within the continental United States, subject to the Interstate Commerce Act, as amended, excluding street, suburban, and interurban electric railways unless operated as a part of a general railroad system of transportation.
Source
40 CFR § 201.1
Scoping language
As used in this part, all terms not defined herein shall have the meaning given them in the Act: