(a)(1) A rail carrier providing transportation or service subject to the jurisdiction of the Board under this part may not subject a person, place, port, or type of traffic to unreasonable discrimination. (2) For purposes of this section, a rail carrier engages in unreasonable discrimination when it charges or receives from a person a different compensation for a service rendered, or to be rendered, in transportation the rail carrier may perform under this part than it charges or receives from another person for performing a like and contemporaneous service in the transportation of a like kind of traffic under substantially similar circumstances. (b) This section shall not apply to - (1) contracts described in section 10709 of this title; (2) rail rates applicable to different routes; or (3) discrimination against the traffic of another carrier providing transportation by any mode. (c) Differences between rates, classifications, rules, and practices of rail carriers do not constitute a violation of this section if such differences result from different services provided by rail carriers.