Article 8 Expiry
The authorisation given by article 3(1) shall cease forthwith if the exempted vehicle is operated on a route other than that between—
(a)
Blaenau Ffestiniog station and Porthmadog station, or
(b)
on the Welsh Highland Railway between Caernarfon station and Rhyd-Ddu station,
unless the Secretary of State has been given written notice in advance specifying the details of the route, and he has given his written approval for the exempted vehicle to be operated on that route.