Tunnel possibility should be properly investigated
Sir,
I tend to agree with Mr Moodie’s view (Argyllshire Advertiser letters, June 18) that the best option at the Rest may be a new surface alignment up the south western side of Glen Croe.
A tunnel, however, remains a possibility which should be properly investigated.
The inclined tunnel proposed by [Transport Scotland consultants] Jacobs would have increased emissions from climbing vehicles and runaway hazards from descending ones, and so should be viewed with some scepticism.
Mr Moodie mentions the need for escape exits, but I would point out that the Laerdal Tunnel doesn’t have these, and neither do the Norwegian and Faeroe undersea road tunnels.
They do have well-thought-out provisions for emergencies which include 24/7 remote monitoring and control of turn-back arrangements.
The point is that if we are seeing relevant experience in mountain road tunnels we won’t find it around south east England.
Jacobs dismissed the south west side of the glen as having ‘much the same slip risks as the existing alignment’.
This is patently not the case.
The slopes of Ben Luibhean have far more run-off gullies than on the south west side, which suggests unusually high rain impact on them.
On the other hand a walk over the two forestry roads on the opposite side of the glen reveals only one small flash flood site on the lower road, and none at all on the higher one.
The slopes above the higher forest road also tend to ease somewhat, particularly those in the eastern corrie of Ben Donich.
I haven’t ploughed through the tree cover, but any significant flash flood events in recent decades would have left their marks on these roads, and I didn’t find any.
The whole argument for that side of the glen turns on its reduced exposure to these risks, and not on the details of road construction there.
These in any case do not appear to be insuperable, after all the forestry lads made a road there with a lot fewer resources than Transport Scotland.
Arthur Blue, Ardrishaig