Rannoch Moor has two railway stations, which seems impossible the moment you stand on the platform and look around. The West Highland Line crosses the moor between Bridge of Orchy and Corrour, opening up country that has no public roads of any kind. The engineers who built it in the 1890s had a problem: the rails were heavy and the bog was bottomless. Their solution was a kind of geological raft. They laid the tracks on a mattress of tree roots, brushwood, and thousands of tons of earth and ashes, and let it float. It still floats. Three ScotRail services run daily from Glasgow Queen Street north toward Mallaig, two on Sundays, the journey taking two and a half hours to Rannoch and another fifteen minutes to Corrour, which at 408 metres is the highest station on the British network. The Caledonian Sleeper from London Euston pulls in around nine in the morning, six nights a week. There are no ticket machines. There are no toilets. The platforms are unstaffed, and once your train rumbles away you are very, very quiet.

The song says: Sure by Tummel and Loch Rannoch and Lochaber I will go, by heather tracks wi' heaven in their wiles. It is called The Road to the Isles, composed by Pipe Major John McLellan in 1917, and Scots have been gleefully spoofing it for a century. The truth is that this was never the main road to the Isles, just muddy cattle trails for drovers heading to market in Aberfeldy and Perth. You would only flee west through Rannoch if you were Bonnie Prince Charlie after Culloden, or Alan Breck in Kidnapped, dodging the Redcoats through the heath. After the '45, the centuries-old life of subsistence farming and feudal tenure ended. Native mixed forest was replaced by commercial conifers. Bogs were drained. Small farms were swept away for sheep and cattle, and the uplands became carpeted in bracken and heather to support deer and grouse for the gentlemen's guns. Sporting rights were the new cash crop. The Victorians romanticised the Highlands, and in 1894 the railway crossed the moor.

The northern half of Rannoch Moor belongs to Corrour Estate, which is owned by Lisbet Rausing, an heir to the Tetra Pak fortune. The southern tract is managed by Scottish Natural Heritage. Both owners are now trying to undo the damage of two centuries of commercial forestry and drainage, restoring the moor to something closer to its original diverse, sustainable habitat. Corrour Lodge among the estate cottages is a remarkable modern building, completed in 2004 to replace Old Corrour Lodge, which had been built in 1896 and destroyed by fire in 1942. The new lodge, reckoned to cost £20 million, was designed by Moshe Safdie in Portuguese granite, steel, and glass. It is sometimes available as a very upmarket holiday let. There was once a third station on the moor, at Gorton, nine miles south of Rannoch. From 1938 to 1960 it served as an unlikely schoolhouse: an old railway carriage placed on the platform, with the teacher riding up each morning from Bridge of Orchy.

All the Highlands have midges in summer, but in the west you meet Culicoides impunctatus, the Great West Highland Mudge. Too small to swat, too numerous to flee, indifferent to most insect repellents. They do not like cold or wind, which is sometimes a comfort. The moor has Munros all around it: Schiehallion, the Fuji-like cone at 1,083 metres reached from the Braes of Foss; Beinn na Lap at 935 metres, walked from the youth hostel on Loch Ossian; and Ben Alder at 1,148 metres, which sits so far from any road that climbing it requires an overnight bivvy. The lochs hold brown trout, pike, charr, and perch. The salmon are rare and may not be taken. The moor has become a perennial location for film: Outlander, Trainspotting, Monty Python and the Holy Grail, Being Human, Harry Potter and the Chamber of Secrets, Rob Roy. If you want an arty promotional video for whisky or craft gin, this is the place. The treeless desolation is the point.