6.—(1) Not less than 28 days before commencing the execution of any works of the type referred to in paragraph 4(2) above that are near to, or will or may affect, any apparatus the removal of which has not been required by Railtrack under paragraph 4(2), Railtrack shall submit to the undertaker in question a plan, section and description of the works to be executed.
(2) Those works shall be executed only in accordance with the plan, section and description submitted under sub-paragraph (1) above and in accordance with such reasonable requirements as may be made in accordance with sub-paragraph (3) below by the undertaker for the alteration or otherwise for the protection of the apparatus, or for securing access thereto, and the undertaker shall be entitled by its officer to watch and inspect the execution of those works.
(3) Any requirements made by an undertaker under paragraph (2) above shall be made within a period of 21 days beginning with the date on which a plan, section and description under paragraph (1) above are submitted to it.
(4) If an undertaker in accordance with sub-paragraph (3) above and in consequence of the works proposed by Railtrack, reasonably requires the removal of any apparatus and gives written notice to Railtrack of that requirement, the foregoing provisions of this Part of this Schedule shall apply as if the removal of the apparatus had been required by Railtrack under paragraph 4(2) above.
(5) Nothing in this paragraph shall preclude Railtrack for submitting at any time or from time to time, but in no case less than 28 days before commencing the execution of any works, a new plan, section and description in lieu of the plan, section and description previously submitted, and thereupon the provisions of this paragraph shall apply to and in respect of the new plan, section and description.
(6) Railtrack shall not be required to comply with sub-paragraph (1) above in a case of emergency but in that case it shall give to the undertaker in question notice as soon as is reasonably practicable and a plan, section and description of those works as soon as reasonably practicable thereafter and shall comply with sub-paragraph (2) above in so far as is reasonably practicable in the circumstances.