In any city affected by the provisions of this act, the judge before whom any civil or criminal cause was tried shall have the same power to set aside a verdict or judgment and grant a new trial thereon, upon legal cause therefor, as circuit courts of the state possess: Provided, That a motion therefor be made in writing and filed with the clerk of the court within 5 days after rendition of the verdict or judgment in said cause, setting forth plainly and briefly the reasons upon which it is made. Affidavits setting forth the facts relied upon shall be filed with said motion. A copy of such motion with the supporting affidavits shall be served upon the adverse party or his attorney at least 2 days before the hearing thereof. Such motion shall be submitted and heard within 1 week after the date of filing, and shall be determined within 2 days after it shall have been submitted and heard. The time for taking an appeal from the judgment or verdict, in case such motion be not granted, shall begin to run from the day such motion is overruled. In no case shall the pendency of such motion stay the issuing and levy of an execution, but in case of a levy under execution pending such motion, no sale of the property so levied upon shall be advertised or made until the final determination of such motion. If such motion be granted, any property levied upon shall be returned forthwith to the adverse party. In case of the absence of the judge before whom such case was tried, the presiding judge or any other judge designated by the presiding judge shall have the authority to hear and determine any such motion.