13.  The Authority must not provide any illumination or illuminated sign or signal on or in  connection with a specified work in the vicinity of any railway belonging to Network Rail unless  it has first consulted Network Rail and it must comply with Network Rail’s reasonable  requirements for preventing confusion between such illumination or illuminated sign or signal and  any railway signal or other light used for controlling, directing or securing the safety of traffic on  the railway.  14.  Any additional expenses which Network Rail may reasonably incur in altering,  reconstructing or maintaining railway property under any powers existing at the making of this  Order by reason of the existence of a specified work must, provided that 56 days’ previous notice  of the commencement of such alteration, reconstruction or maintenance has been given to the  Authority, be repaid by the Authority to Network Rail.  15. —(1) The Authority must pay to Network Rail all reasonable costs, charges, damages and  expenses not otherwise provided for in this Schedule which may be occasioned to or reasonably  incurred by Network Rail—  and the Authority must indemnify and keep indemnified Network Rail from and against all claims  and demands arising out of or in connection with a specified work or any such failure, act or  omission: and the fact that any act or thing may have been done by Network Rail on behalf of the  Authority or in accordance with plans approved by the engineer or in accordance with any  requirement of the engineer or under his supervision does not (if it was done without negligence  on the part of Network Rail or of any person in its employ or of its contractors or agents) excuse  the Authority from any liability under the provisions of this sub-paragraph.  (2) Network Rail must give the Authority reasonable notice of any such claim or demand and no  settlement or compromise of such a claim or demand is to be made without the prior consent of  the Authority.  (3) The sums payable by the Authority under sub-paragraph (1) include a sum equivalent to the  relevant costs.  (4) Subject to the terms of any agreement between Network Rail and a train operator regarding  the timing or method of payment of the relevant costs in respect of that train operator, Network  Rail must promptly pay to each train operator the amount of any sums which Network Rail  receives under sub-paragraph (3) which relates to the relevant costs of that train operator.  (5) The obligation under sub-paragraph (3) to pay Network Rail the relevant costs is, in the  event of default, enforceable directly by any train operator concerned to the extent that such sums  are payable to that operator under sub-paragraph (4).  “the relevant costs” means the costs, direct losses and expenses (including loss of revenue)  reasonably incurred by each train operator as a consequence of any restriction of the use of  Network Rail’s railway network as a result of the construction, maintenance or failure of a  specified work or any such act or omission as mentioned in subparagraph (1); and  “train operator” means any person who is authorised to act as the operator of a train by a  licence under section 8 (licences) of the Railways Act 1993.  16.  Network Rail must, on receipt of a request from the Authority, from time to time provide the  Authority free of charge with written estimates of the costs, charges, expenses and other liabilities  for which the Authority is or will become liable under this Schedule (including the amount of the  relevant costs mentioned in paragraph 15) and with such information as may reasonably enable the  Authority to assess the reasonableness of any such estimate or claim made or to be made under  this Schedule (including any claim relating to those relevant costs).  71 (6) In this paragraph—  (a) by reason of the construction or maintenance of a specified work or the failure of such a  work; or  (b) by reason of any act or omission of the Authority or of any person in its employ or of its  contractors or others whilst engaged upon a specified work, 