Paragraph 46
Network Rail shall before commencing construction of any specified work including any temporary works supply to BW proper and sufficient plans of that work and such further particulars available to it as BW may within 14 days of the submission of the plans reasonably require for the approval of the engineer and shall not commence such construction of any specified work until plans of that work have been approved in writing by the engineer or settled by arbitration.
The approval of the engineer under sub-paragraph (1) shall not be unreasonably withheld or delayed, and if within 56 days after such plans (including any other particulars reasonably required under sub-paragraph (1)) have been supplied to BW the engineer has not intimated his disapproval of those plans and the grounds of his disapproval he shall be deemed to have approved the plans as submitted.
When signifying his approval of the plans the engineer may specify—
any protective work (whether temporary or permanent) which is reasonably necessary to be carried out before the commencement of any specified work to prevent detriment; and
such other requirements as may be reasonably necessary to prevent detriment,
and such protective work shall be constructed by Network Rail with all reasonable dispatch and Network Rail shall not commence the construction of any specified work until the engineer has notified Network Rail that the protective work has been completed to his reasonable satisfaction.