18.—(1) For the protection of sewerage undertakers the following provisions shall, unless otherwise agreed in writing between Network Rail and the sewerage undertaker concerned, have effect.
(2) In this part of this Schedule—
“construction” includes placing or altering; and “constructed” shall be construed accordingly;
“plan” includes sections and method statements;
“sewer” means a public sewer within the meaning of the Water Industry Act 1991 and includes a disposal main within the meaning of that Act;
“specified work” means so much of the authorised works as will or may be situated over or within 15 metres measured in any direction of, or (wherever situated) impose any load directly upon, any sewer; and
“the undertaker” means the sewerage undertaker for the area of the works or whose sewers are affected.
(3) The provisions of Schedule 12 to this Order shall not apply in relation to apparatus to which this Part of this Schedule applies.