If any passenger tramway is found to be, in the judgment of the department, dangerous to public safety or is being operated without the operating certificate required in section 29-204 or is being operated in violation of any regulation adopted under this chapter, the department may require the operator of such passenger tramway to discontinue its operation forthwith. When a passenger tramway has been placed out of service pursuant to this section, the operator of such tramway shall not again operate such tramway until repairs have been made, an operating certificate has been obtained, or the violation is discontinued and permission given by the commissioner or his authorized agent to resume operation of such tramway.