6.—(1) In constructing or maintaining any of the new railways, the undertaker may—
(a)deviate laterally from the lines or situations shown on the deposited plans within the limits of deviation relating to that railway shown on those plans; and
(b)deviate vertically from the levels shown on the deposited sections—
(i)to any extent not exceeding 3 metres upwards; and
(ii)to any extent downwards as may be found to be necessary or convenient.
(2) Without limiting the scope of paragraph (1), in constructing or maintaining the new railways the undertaker may, to the extent it thinks fit, deviate from their points of commencement and termination shown on the deposited plans.