Idaho Code § 61-318
Every common carrier shall afford all reasonable, proper and equal facilities for the prompt and efficient interchange and transfer of passengers, tonnage and cars, loaded or empty, between the lines owned, operated, controlled or leased by it, and the lines of every other common carrier, and shall make such interchange and transfer promptly without discrimination between shippers, passengers or carriers either as to compensation charged, service rendered or facilities afforded. Every railroad corporation shall receive from every other railroad corporation at any point of connection, freight cars of proper standard and in proper condition, and shall haul the same either to destination, if the destination be upon the lines owned, operated or controlled by such railroad corporation, or to a point of transfer according to route billed, if the destination be upon the line of some other railroad corporation.
Nothing in this section contained shall be construed as in any other wise limiting or modifying the duty of a common carrier to establish joint rates, fares and charges for the transportation of passengers and property over the lines owned, operated, controlled or leased by it and the lines of other common carriers nor as in any manner limiting or modifying the power of the commission to require the establishment of such joint rates, fares and charges.
Idaho Code § 61-318