If, after investigation, the commissioner of safety or the board finds that a violation of any of the rules exists, or that there is a condition in passenger tramway construction, operation or maintenance endangering the safety of the public, either the commissioner of safety or the board shall forthwith issue a written order setting forth his or its findings, the corrective action to be taken, and fixing a reasonable time for compliance therewith. Such order shall be served upon the operator involved by registered mail, and shall become final, unless the operator shall apply to the board for a hearing in the manner hereinafter provided.