16Making such provision as in the opinion of the Secretary of State is equivalent to that which would be required—
(a)for keeping the works comprised in the crossing and any additions to or improvements of those works insured during the relevant period against damage not amounting to complete destruction of all works so comprised;
(b)for insuring against liabilities arising from the Secretary of State’s ownership or occupation of any such works, additions or improvements, or from anything done or omitted in the course of any operations carried out by or on behalf of the Secretary of State in the exercise of any of his functions under this Act or of any functions mentioned in paragraph 14(b) above;
if those works, and any such additions or improvements, were owned and maintained by a commercial undertaking.