Rumour has it that the river Tua is to be dammed for hydro- electric power. Some say work will start in 2002, others that it won't for five or 10 years, or even that it will never be built. If the project does go ahead, those most directly affected will be the villagers whose principal lifeline to the rest of the country is the narrow-gauge branch line which winds along the rocky ravines of the Tua valley, way below the proposed high-water level.
The line starts at tiny Tua village, where the tributary tumbles into the mighty Douro river which bisects the country horizontally. This is the heart of port wine-growing country. All around are mountains, their surfaces carved into geometric shapes by terraced vineyards which have been hewn out of rock and schist.
In contrast with the fine old stone houses of the port-growing quintas (estates), Tua consists of a few scruffy houses scattered about the station. A sad little steam tank engine sits in a siding, rusting and neglected. This was the locomotive which retired in 1983 after decades of service hauling a pair of wooden-slatted carriages up the Tua line to Braganza in the far north-east corner of the country. I remember it from my childhood, when I lived in northern Portugal.
For old times' sake, I recently rode the Tua line. The branch has been pruned back as far as Mirandela - about half its former length - and nowadays a bright orange diesel pulls the train. We clanked slowly up a gorge of lavish views over vineyards, craggy peaks above and gushing white water below. Long shrill hoots announced well in advance our arrival at each village.
Every stop involved a major upheaval in our crowded second-class carriage, as passengers made way for bundles of cabbages and cardboard boxes of chickens to be lugged on and off. After a couple of hours we left the ravines, lofty passes and wine estates behind, and trundled on to the undulating upland plain of Trs-os-Montes (literally, "behind the mountains"). As we eased into Mirandela, the new terminus, my seat-mate Joaquim Santos, a medical student in Oporto returning on leave to his village, told me: "I continue by bus now. Maybe next time it will be bus all the way. Or maybe not. All we need is a miracle to save the Tua - like the one which stopped the Coa valley dam."
The Coa is another, still more remote, tributary of the Douro, joining further upstream, 15km short of the Spanish frontier. Until 1991 it was a backwater, forgotten by all except the port company Ramos Pinto, which grew some of its finest quality grapes on its banks, and EDP, the Portuguese electricity-generating company. The latter began work that year on a 100m-high dam across a gorge near the Coa's mouth. Four years, and at least pounds 200m later, the project was abandoned.
According to Joao Nicolau d'Almeida, Ramos Pinto's wine-maker, who was at the vanguard of a bitter fight against the dam: "The discovery that the Coa valley is one of the world's most important Palaeolithic sites, with tens of thousands of rock engravings, was a miracle. Nothing less. It forced the government to halt the project, and so saved the Coa valley from total destruction by flood."
To reach the Coa, I had continued on up the main Douro line which snakes eastwards along the water's edge. It crosses from the north bank to the south, and passes two of the five massive dams which, in the 1970s and 1980s, changed the Douro from tortuous rapids and whirlpools into a series of placid, serpentine lakes. This project completed, EDP's next target was the tributaries.
From Pocinho, the end of the line near the Coa's confluence with the Douro, I drove with Joao Nicolau d'Almeida to Muxagata, a farming village with a medieval pillory on the cobbled main square. Opposite, the old granite prison has been turned into an air-conditioned visitor centre for the newly formed Foz Coa Archaeological Park, due to become a Unesco World Heritage Site next year. …