There are 39 tunnels on the 80km stretch of line that cuts through the heart of the Black Forest, from Villingen in the south to Offenburg on the Rhine, linking the little towns of St Georgen, Triberg, Hornberg and Gutach. As we left St Georgen the train entered the first tunnel; from then on, green meadows gave way to pine-clad valleys as we plunged further into the Gutachtal.
The train pulled in to Triberg, a cleft between granite rocks with a platform, a cafe and a taxi rank; the town itself was missing. It was a good five-minute taxi-ride to the top of Triberg's hill and the town with its waterfall and cuckoo clocks, Black Forest museum and miraculous singing picture of the Virgin in the church of Maria in der Tanne.
I stayed in Parkhotel Wehrle, a splendid 18th-century inn on the high street, heavy with oak panelling and elegant period furniture, and set beside gardens that melt into the forest. The whole town has been shoe- horned into the pine-covered hills; so much resin-scented air to breathe has given it a reputation as a health resort.
At the top of the high street is the tallest waterfall in Germany. Coal- black squirrels chattered and leapt beside the path as I puffed my way up to the top to look out at the view. The water fell 162m in seven great cascades, beyond which I could see the roofs and spires of the town sitting narrowly between pine-covered hills.
The Black Forest was extremely popular with the Victorians, who were aided and abetted in their search for accessible wilderness by the railway and the newly formed Schwarzwaldverien - the Black Forest Society. In 1864, some of the locals in Freiberg got together to think of a way of bringing tourists to the area. They came up with Germany's first rambling association; then, in 1900, they created the world's first long-distance footpath, the Westweg, which cuts 281km through the Black Forest to Basle in Switzerland.
Now there are over 20 long-distance paths traversing the forest. The Clock Carriers' Way - a nine-day round robin walk visiting the little towns on the route of 17th- and 18th-century traders who bought up forest- made clocks - begins at the top of the waterfall.
Clocks are still big business in the Black Forest and nowhere more so than Triberg. All up and down the high street is a cheerful clutter of shops selling nothing but clocks. The traditional cuckoo clock may not be the grandest souvenir, but it is surely one of the first brought back on trains steaming across Europe. The Schwarzwaldbahn itself opened in 1873, having been 11 years in the building. Its engineer and one of the century's great geniuses, Robert Gerwig, blasted through the hills putting in two double horseshoes to climb to 450m in a handful of miles. It was a triumph of engineering; and with the opening of the line, the old, isolated way of life began to disappear.
If you really want to get a taste for the way things were, you must go to the open-air museum near Gutach. A new station at the museum itself is due to open in May 2000. But until then you must do as I did and travel on to Gutach, from where you can take a half-hour walk or a five-minute taxi ride to the Schwarzwalder Freilichtmuseum. It is, of course, a recollection of times past, centred around five great, hip-roofed farmhouses which lie in the sun like so many beached leviathans. In any one of these a family might be holed up from the first snowfall of November until May. A man might live here and never go out of doors for six months at a time, because beneath the thatched roof are kitchen and stable, living quarters and hay barn, dairy, cattle byre and corn store with space to spare for wagons and bee hives.
They are an endangered species, these Black Forest farmhouses, too big, too old, too primitive to survive. In centuries gone by their wooden frames and shaggy, thatched roofs burnt down often, only to be resurrected like Lazarus, with their "God" corners on the inside and crucifixes on the outside. If one were to burn down today, no one would have the heart to rebuild it because no one wants to live in them now.
The Vogtsbauernhof, the original farmhouse which has been here since 1570, was lived in until it was taken over in 1964 to form the nucleus of the present-day museum. Barbara Aberle, the last owner-farmer stayed on for a year until, finding herself as much an exhibit as the house, moved out to a new house on the other side of the tracks. Now the Aberle family sells snacks to the visitors who come on the train that altered their lives for ever.
Carolle Doyle paid pounds 166 by rail from London to Triberg, made up as follows: Eurostar London - Cologne return pounds 85 (6 hours); Deutsche Bahn Cologne - Triberg return pounds 82 (4 hours 30 minutes). She paid pounds 16 for a "Feiren Pass Area 38" which gives a week's travel on Schwalzwaldbahn. Fares can be booked through Deutsche Bahn (0171-317 0919), but note that the cost of a London-Cologne return is now pounds 82.
Accommodation Triberg - Parkhotel Wherle (0049 7722 86020, fax: 7722 860290) is one of the "romantik hotels", a chain noted for its period atmosphere. From pounds 60 per night. The local tourist office (0049 7722 953230, fax: 771 857228) has a full accommodation list.
Schwarzwalder Freilichtmuseum (0049 7831 230, fax: 7831 839 87) is open April- October from 8.30am-6pm. Cost DM4Reuse content