Ohio Rev. Code Ann. § 4909.31

Whenever a joint rate or charge is ordered substituted by the public utilities commission, and the railroads party thereto fail to agree within twenty days after the service of such order upon the apportionment of such rate or charge, the commission may, after a hearing, issue a supplemental order declaring the apportionment of such joint rate or charge, which shall take effect of its own force as part of the original order.