(a) No president, director, officer, agent, or employee of any railroad shall be interested, directly or indirectly, in the furnishing of materials or supplies to the railroad or in the business of transportation as a common carrier of freight or passengers over the works owned, leased, controlled, or worked by the railroad, nor in any arrangement which shall afford more advantageous terms or greater facilities than are offered or accorded to the public.
(b) All contracts and arrangements in violation of this section shall be void.