15(1)Subject to sub-paragraph (2) below, where an order has been made with respect to a bridge other than a trunk road bridge—
(a)requiring the reconstruction or improvement of the bridge, or of the highway carried by the bridge, or of the approaches to the bridge, or
(b)relating to the maintenance of the bridge, or of any such highway or approaches, or
(c)relating to the operation of the bridge, being a swing bridge,
the expense of such reconstruction, improvement, maintenance or operation shall be defrayed either by the owners of the bridge or by one or more of the highway authorities entitled to make application with respect thereto by virtue of section 95 of this Act, or partly by the owners of the bridge and partly by one or more of those highway authorities, as, in default of agreement, may be determined by arbitration.
(2)Sub-paragraph (1) above is subject to the following, namely that, unless otherwise agreed,—
(a)where the bridge is a bridge crossing a railway of railway undertakers, or a canal of canal undertakers, or a railway, lock, passage or other work of dock undertakers or of harbour undertakers, any additional expense incurred by the owners of that railway, canal, lock, passage or work by reason of any alteration thereof due to the provisions of the order (other than provisions applied for by the undertakers for the improvement of their undertaking) shall be defrayed by one or more of the highway authorities;
(b)where the bridge is a swing bridge, any additional expense incurred by the owners in relation to the operation of the bridge due to the provisions of the order (other than provisions applied for by the owners for the improvement of their undertaking) shall be defrayed by one or more of the highway authorities; and
(c)except so far as any additional expense is due to works executed at the instance of the owners of the bridge for the improvement of their undertaking, the owners' share of the expense of the reconstruction, improvement, maintenance or operation shall be an amount equivalent to what would have been the amount of the owners' liability if no such order had been made.