In the event that the grantee shall become insolvent, or be declared bankrupt, or the property of the grantee shall come into the possession of any receiver, assignee or other officer acting under an order of court, and any such receiver, assignee or other such officer shall not be discharged within 60 days after taking possession of such property, the city may, at its option, terminate the franchise by giving written notice thereof to the grantee.