1(1)The scheduled works must be constructed—U.K.
(a)in the lines or situations shown on the deposited plans,
(b)in accordance with the levels shown on the deposited sections, and
(c)in the case of any station, depot or shaft for which an upper limit is shown on the deposited sections, within the limit so shown.
This is subject to sub-paragraph (2).
(2)In constructing or maintaining any of the scheduled works, the nominated undertaker may deviate—
(a)laterally to any extent from the lines or situations shown on the deposited plans, within the limits of deviation so shown,
(b)vertically downwards to any extent from the level shown for that work on the deposited sections, and
(c)vertically upwards to any extent not exceeding 3 metres from the level shown for that work on the deposited sections, but doing so in a case mentioned in sub-paragraph (1)(c) does not increase the limit referred to in that sub-paragraph.