Mich. Comp. Laws § 462.4

Sec. 4. (a) Every common carrier is hereby required to furnish reasonably adequate service and facilities and shall provide and furnish transportation of passengers and property upon reasonable requests therefor, and all charges made for any service in connection therewith, or for the receiving, switching, delivering, storing, transporting or handling of such persons or property shall be reasonable and just, and every unjust and unreasonable charge for such service is prohibited and declared to be unlawful; (b) All railroads incorporated under the general railroad law of this state, as between themselves, and all electric railroads, as between themselves, shall establish through routes and just and reasonable rates applicable thereto, except as hereinafter provided; (c) Whenever passengers or property are transported over 2 or more connecting lines of railroad between points in this state, and the railroad companies have made joint rates for the transportation of the same, such rates and all charges in connection therewith shall be just and reasonable, and every unjust and unreasonable charge is prohibited and declared to be unlawful: Provided, That a less charge by such railroads for their proportion of such joint rates than is made locally between the same points on their respective lines shall not for that reason be construed as a violation of the provisions of this act, nor render such railroads liable to any of the penalties hereof.