I think there's a need to look at the wording of this subject: it's the alternative routeing between Exeter and Plymouth that's being considered. Given the large stretches of railway and railway land extant then an obvious candidate for such a proposal would be via Okehampton and then connecting to the Gunnislake branch with new build, but the question of how many passengers would be using Okehampton or even Tavistock is almost incidental, and could be considered a bonus. In other words, what case would there be for this route without any stations on it whatsoever, non-stop? If there can begin to be an economic case constructed, then start to factor in Tavistock etc in the hope that those figures might just tip the balance. I can well understand the scepticism shown by many towards this, but your view is probably in part determined by how you regard the possibility of a breach of the line in the Dawlish area in the immediate future. I happen to believe there's a very real chance that the line could not only be breached again within the next decade, say, but that it could suffer much more catastrophically than before. If half a billion or less could achieve an alternative route (which some say is possible) then I think the SW proper (not pretend SW like Bristol and Bath, which are becoming outer Western suburbs of London) deserves to have this spent, in part as recompense for lack of transport infrastructure spending over decades.