3.—(1) Network Rail may construct and maintain the work, comprising a footbridge over the West Anglia Main Line railway lines, commencing at a point 56 metres south-east of the junction of Marsh Lane with Park Avenue Road and terminating at a point 75 metres east of that junction.
(2) Subject to article 4 (power to deviate), the work may only be constructed in the lines or situations shown on the deposited plans and in accordance with the levels shown on the section.
(3) Network Rail may carry out and maintain such of the following works as may be necessary or expedient for the purposes of, or for purposes ancillary to, the construction of the work, namely—
(a)demolition of the existing footbridge over the West Anglia Main Line railway lines within Northumberland Park station;
(b)electrical equipment and signalling works;
(c)ramps, means of access and footpaths; and
(d)works to install or alter the position of apparatus, including mains, sewers, drains and cables.
(4) Network Rail may carry out such other works (of whatever nature) as may be necessary or expedient for the purposes of, or for purposes ancillary to, the construction of the work, other than works that would interfere with a navigable watercourse.
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.