Power to deviate
4. In constructing or maintaining the work, Network Rail may—
(a)deviate laterally from the lines or situations shown on sheet 1 of the deposited plans to the extent of the limits of deviation for the work; and
(b)deviate vertically from the levels shown on the section—
(i)to any extent not exceeding 3 metres upwards; or
(ii)to any extent downwards as may be found to be necessary or convenient.