42.  If at any time after the completion of a specified work or a protective work, not being a work  vested in Network Rail, Network Rail gives notice to the undertaker informing it that the state of  maintenance of any part of the specified work or the protective work appears to be such as  adversely affects the operation of railway property, the undertaker must, on receipt of such notice,  take such steps as may be reasonably necessary to put that specified work or that protective work  in such state of maintenance as not adversely to affect railway property.  43.  The undertaker must not provide any illumination or illuminated sign or signal on or in  connection with a specified work or a protective 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.  44.  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 or a protective work must, provided that 56  days’ previous notice of the commencement of such alteration, reconstruction or maintenance has  been given to the undertaker, be repaid by the undertaker to Network Rail.  45. —(1) The undertaker must pay to Network Rail all reasonable costs, charges, damages and  expenses not otherwise provided for in this Part of this Schedule which may he occasioned to or  reasonably incurred by Network Rail—  and the undertaker 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 a protective 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 undertaker or in accordance with plans approved by the engineer or  in accordance with any requirement of the engineer or under his supervision must 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 undertaker from any liability under the provisions of this sub- paragraph.  (2) Network Rail must give the undertaker reasonable notice of any such claim or demand and  no settlement or compromise of such a claim or demand must be made without the prior consent  of the undertaker.  (3) The sums payable by the undertaker under sub-paragraph (1) must include sums 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  would be payable to that operator under sub-paragraph (4).  (6) In this paragraph—  “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 protective work or any such act or omission as mentioned in sub-paragraph  (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.  139 (a) by reason of the construction or maintenance of a specified work or a protective work or  the failure thereof; or  (b) by reason of any act or omission of the undertaker or of any person in its employ or of its  contractors or others whilst engaged upon a specified work or a protective work, 