4. Regardless of the effect of article (1) (transfer of rights and obligations to undertaker, etc), the undertaker must not—
(1) without the consent in writing of the Office of Rail and Road and Highways England operate—
(a)railway no. 1 at the point where it is crossed by the A5 trunk road at Pentre Clawdd; and
(b)railway no. 2 at the point where it is crossed by the A483 trunk road at Weston,
and such crossings must not be on the level; and
(2) without the consent in writing of the Office of Rail and Road operate —
(a)railway no.4 at the point where it crosses the A495 in Porth-y-waen; and
(b)railway no.4 at the Porth-y-waen School crossing,
over the level crossings at those points.