The commission may investigate all existing or proposed interstate rates, fares, tolls, charges, and classifications, and all rules and practices in relation thereto, for or in relation to the transportation of persons or property or the transmission of messages for conversations, where any act in relation thereto takes place within this state and when they are, in the opinion of the commission, in violation of federal law, or in conflict with the rulings, orders, or regulations of the a federal agency, the commission may apply for relief by petition or otherwise to the federal agency that has jurisdiction over the alleged violation or to any court of competent jurisdiction.