Investigating rates upon its own motion.

If the public utilities commission believes that any rate or charge may be unreasonable or unjustly discriminatory, and that an investigation relating thereto should be made, it may investigate them upon its own motion. Before such investigation it shall present to the railroad a statement in writing setting forth the rate or charge to be investigated. Thereafter, on ten days' notice to the railroad of the time and place of such investigation, the commission may proceed to investigate such rate or charge in the same manner and make like orders in respect thereto, as if such investigation had been made upon complaint.When any schedule is filed with the commission stating a new individual or joint rate or charge, any new individual or joint classification, or any new individual or joint regulation or practice affecting any rate or charge, the commission may, either upon complaint or upon its own initiative without complaint, at once, and if it so orders, without answer or other formal pleading by the interested carriers, but upon reasonable notice, enter upon a hearing concerning the propriety of such rate, charge, classification, regulation, or practice. Pending such hearing and the decision thereon, the commission upon filing with such schedule and delivering to the carriers affected thereby, a statement in writing of its reasons for such suspension, may suspend the operation of such schedule and postpone the use and operation of such rate, charge, classification, regulation, or practice, for a period of not longer than one hundred twenty days beyond the time when such rate, charge, classification, regulation, or practice would otherwise go into effect. After a full hearing, whether completed before or after the rate, charge, classification, regulation, or practice goes into effect, the commission may make such order in reference to such rate, charge, classification, regulation, or practice as would be proper in a proceeding initiated after the rate, charge, classification, regulation, or practice, had become effective. If any such hearing cannot be concluded within such period of suspension, the commission may extend the time of suspension for a further period not exceeding thirty days. At any hearing involving a rate increased or a rate sought to be increased, the burden of proof to show that the increased rate or the proposed increased rate is just and reasonable is upon the common carrier, and the commission shall give to the hearing and decision of such question preference over all other questions pending before it and decide the same as speedily as possible.A full record shall be kept of the proceedings before the commission on such investigations. All testimony shall be taken by the stenographer appointed by the commission.