WITH reference to the letter from Rodney Smith of Lydford regarding the Okehampton line, he is correct about it being impossible to reinstate the old GW line through to Tavistock. However, reinstating the old Southern line from Okehampton is by no means as impossible as he suggests — if it were then Network Rail would not have gone to the trouble of surveying the route after the Dawlish disaster and the Transport Minister Patrick Mcloughlin would not have bothered to take a special train to Okehampton to see for himself! Furthermore, it was in fact the cheapest of all the practical options, with boring tunnels under Halden Ridge on the existing line being by far the most expensive. In any case, why should an important town like Tavistock be left out as Mr Smith suggests? As for reopening the lines to North Cornwall, via Halwill Junction, this is pure fantasy as much of the trackbed has gone, whereas almost all of it is intact between Bere Alston and Okehampton. In any case if the Okehampton route is reopened it has been suggested that an additional station should be built at Sourton to cater for traffic from that area.      Nobody is saying that the Dawlish route should not be strengthened and preserved, but being cut off by rail from the rest of the country cannot be allowed to happen again and it should be remembered that it provides the only way in or out of Plymouth. Even if a Dawlish avoiding line was built, it would still mean that if anything goes wrong on another part of that line there will again be no trains at all unless the Okehampton line is reopened as an alternative route to Exeter and beyond. It is difficult to see why some people are so against something that can only be of benefit to this area in particular and the whole of the South West in general.                                                     Paul Mercer Peter Tavy YOUR correspondent Rodney Smith's letter (Times, May 6) was difficult to understand. No one is suggesting reopening the old GWR line which has been extensively built on. But there has been little building on the old LSWR line. The foundational infrastructure is mainly in place and it ought to be fairly easy to restore, if there was a will to do so. By no means 'impossible!' Yes, Plymouth does have a rail route to Exeter, but Tavistock doesn't. It is difficult to see why Mr Smith wants Tavistock to be bypassed. Tavistock and Okehampton are sizable towns and growing. They ought to have a main line rail service restored as soon as possible, which would also provide an alternative service in the event of any future disruption at Dawlish. This is the scheme that has the most to offer. I just wish somebody would get on with it. Terence Scarborough Tavistock