Comboio Presidencial

In 1890, the French firm Désouches David & Cie built three railway saloons for the kings of Portugal: a Ministers' Salon, a Restaurant Salon, and a Salon for the entourage and the security men. They were the royal train — panelled, gilded, and entirely serious about what they were for.

Twenty years later the monarchy was gone. Portugal became a republic in 1910, and a republic has no use for a royal train.

Except it did. Rather than break the carriages up, the new state simply renamed them. From 1910 the same saloons went on carrying the head of state around the country — as the Comboio Presidencial, the Presidential Train. In 1930 a fourth carriage joined them, the Head of State salon, built by Linke-Hofmann Busch in Germany with green-toned interiors, a vestibule, a kitchen and the president's own quarters; you can still see it lettered S 5 on the carriage side. In 1940 the originals were rebuilt at the Barreiro workshops and two more vehicles were added — a van, and a Journalists' Carriage, a first-class compartment car for the travelling press, which tells you exactly what these journeys were.

Six carriages. Kings, then presidents. Marshal Óscar Carmona, Admiral Américo Tomás, Marshal Craveiro Lopes; Queen Elizabeth II's entourage when she came in 1957. Mostly Lisbon to Porto, with the security laid on.

And then, on 30 July 1970, it made its last notable journey: carrying Salazar's funeral cortège from Lisbon to Santa Comba Dão. Eighty years of Portuguese power had ridden in these rooms, and that was the end of it. The train went to a museum and stayed there for forty years.

It came back. Restored between 2009 and 2013 at the National Railway Museum in Entroncamento — which still owns it — it now runs a handful of Saturdays a year on the Linha do Douro, out of Porto-São Bento and up the river as far as Ferradosa, with a menu by Chef Chakall and the wines of the estates you are rolling past.

It costs €750, and it is not a train journey in any ordinary sense. It is a day inside a national museum piece that happens to be moving through a UNESCO wine landscape while someone pours you a glass. If that sounds absurd, it is — gloriously, and on purpose.

It begins at Porto-São Bento, which is the right place for it. The station hall is lined floor to ceiling with azulejos — great blue-and-white panels of Portuguese history, battles and harvests and royal processions — and you walk through all of it to reach a platform where six deep-blue carriages are standing with a red stripe along their flanks and the Portuguese coat of arms carved and bolted to the side.

Departure is 10:50. There is no hurry to any part of this day.

The Linha do Douro leaves Porto and takes a while to become itself: suburbs, then the river, and then — somewhere past Régua — the thing everyone comes for. The Douro is the oldest demarcated wine region in the world and a UNESCO World Heritage landscape, and the railway has the best seat in it, running the north bank on a ledge above the water with the terraces stacked up the hillsides above. In places the track is so close to the river that the whole train seems to be floating.

Inside, you are in rooms that are frankly hard to sit in casually. Panelled wood, brass, upholstered benches, a piano. These are the saloons where cabinet ministers sat, and where a president had his own quarters behind a door marked for him alone. There is live music in the carriages. Lunch is Chakall's, built out of the cooking of the north, and the wines are poured by the estates themselves — Rozés – Quinta do Grifo, Vallado, Vale D. Maria — which means you are frequently drinking something grown on a hillside currently going past the window.

The train runs up as far as Ferradosa, and the excursion goes up from there to São João da Pesqueira and its Museu do Vinho, a permanent exhibition about the only subject this valley has ever really had. Then back down the river, with the light going long and gold across the terraces, which is when the Douro is at its best and when — not coincidentally — the train has arranged for you to be looking at it.

You are back at São Bento at 21:55. Eleven hours, most of it barely moving.

The odd thing, and the thing that stays with you, is what you have actually been sitting in. Not a replica, not a themed carriage: the real vehicles, the ones that carried the kings and then the presidents and then the coffin. A museum piece with a table in it — and the museum let you eat at the table.

The Presidential Train runs a handful of Saturdays a year, in two short seasons. It is not a scheduled service and there is no turning up for it.

How the day runs:

Good to know:

• Two seasons, both short. Roughly April to early June, and again from about late September into October — Saturdays only, and only a few of them. CP publishes the dates each year and they move, so confirm before you build a trip around it.
• Autumn is the one. The Douro at harvest, with the terraces turning, is the valley at its absolute best — and it is also when the train sells out first.
• This is one price for everything. The menu, the wines, the music and the off-train visit are the product; there are no classes to choose between.
• It's a long, slow, seated day. Eleven hours, most of it at a table. That is the point, but go in knowing it — this is not a sightseeing trip with a restaurant attached.
• Book far ahead. Six carriages, a few Saturdays a year, and a lot of interest.
• If it's sold out, the valley isn't. The ordinary Linha do Douro regional train runs the same river every day for a few euros, and the view out of the window is identical.

Tickets come from CP – Comboios de Portugal, who run the train with the National Railway Museum Foundation and Chef Chakall. CP's published price is €750 a passenger, and that is the whole thing: the day, the menu, the wines, the music and the visit ashore. There is no upgrade to buy and no class system — one train, one price. It runs a few Saturdays in autumn, at harvest and in colour, and a few more in spring with the valley green.

Dates change every year and the seasons are tiny — a handful of Saturdays, six carriages — so treat the date as the fixed point of the trip rather than something to fit in, and start in Porto the night before. If the price rather than the date is the obstacle, the ordinary Douro line train gives you the same river and the same terraces; what you are paying for here is the carriages.

The train gives you the Douro through a window and a wine glass. The valley deserves that you get out and walk around in it — which is the argument for building a few days around the Saturday rather than treating it as a day trip from Porto.

Régua and Pinhão are both worth stopping at properly, and both are covered on the Douro line, which runs the same rails on an ordinary ticket every day of the week.

The train starts and ends at Porto-São Bento on the same day, so there is nothing to book along the line — you sleep in Porto, on both sides of it.

Stay somewhere you can walk to São Bento from. Porto's centre is compact and hilly and the station sits in the middle of it, so anywhere around the Baixa, Ribeira or Cedofeita puts you ten or fifteen minutes from the platform on foot. The city has the full range, from serious design hotels in restored townhouses down to a very good hostel scene, and prices are still gentler than most Western European cities of its pull.

Two things worth planning:

• Arrive the night before. A 10:50 departure is not brutal, but €750 is a lot to risk on a delayed flight, and Porto is not a city you want to see only from a taxi window.
• Keep the evening after free. You return at 21:55 having eaten and drunk for eleven hours. Do not book dinner.

If you are making a trip of the valley rather than a day of it, the better move is to sleep in the Douro and come back to Porto for the train — or to do the train and then head up the line afterwards on an ordinary service. Pinhão and Peso da Régua both have hotels and both are on the railway; and the real luxury of the region is the quintas, the wine estates, many of which take guests. Waking up on a terrace above the river, having ridden through it the day before, is the correct order to do this in.