First. The term “carrier” includes any railroad subject to the jurisdiction of the Surface Transportation Board, any express company that would have been subject toas of,,and any company which is directly or indirectly owned or controlled by or under common control with any carrier by railroad and which operates any equipment or facilities or performs any service (other than trucking service) in connection with the transportation, receipt, delivery, elevation, transfer in transit, refrigeration or icing, storage, and handling of property transported by railroad, and any receiver, trustee, or other individual or body, judicial or otherwise, when in the possession of the business of any such “carrier”: Provided, however, That the term “carrier” shall not include any street, interurban, or suburban electric railway, unless such railway is operating as a part of a general steam-railroad system of transportation, but shall not exclude any part of the general steam-railroad system of transportation now or hereafter operated by any other motive power. The Surface Transportation Board is authorized and directed upon request of the Mediation Board or upon complaint of any party interested to determine after hearing whether any line operated by electric power falls within the terms of this proviso. The term “carrier” shall not include any company by reason of its being engaged in the mining of coal, the supplying of coal to a carrier where delivery is not beyond the mine tipple, and the operation of equipment or facilities therefor, or in any of such activities.
45 USC § 151
When used in this chapter