A few decades ago couchettes connected Calais with Nice, Plymouth with Edinburgh, and even London with Milford Haven via Cardiff and Swansea. Low-cost airlines ruined such routes, as did rail strikes and a generally shoddy service. It seemed Europe’s sleeper trains had reached their final destination.

Until this week. After a 17-year hiatus, the Brussels to Vienna night train has resumed service. The reinstated route isn’t a touristic trundle down a heritage line. By 2022, the 27 overnight services operated by Austrian Railways (ÖBB) will feature en-suite showers for sleeper cabin guests, plus ‘mini-suite’ couchettes that look akin to Japanese pod hotels. They are very much the trains of the future.

And more sleeper services are on the horizon. Overnight rail routes are being inaugurated – or reintroduced – in Turkey, Italy and Sweden, each one replete with fresh linen and fabulous views. So why the sudden interest?

Of course there’s the romance. It’s either an airport schelp followed a 60-minute march through security, then a departure gate dash that will add 3,000 steps to your Fitbit, or a city centre departure with a check-in time of mere minutes. And that’s before you’ve even boarded.

Europe’s premier trains will beguile Britons used to our home-grown ‘First Class’. Think free red wine or prosecco (in France and Italy). Complimentary chocs (in Belgium and Austria). Or armchair seats and push-button waiter services, while a telegenic topography stars in the background (most other countries). It sure beats an M&S cheese sandwich (£3.95 on BA).

There’s a final reason for all the fuss. One that’s very much travel’s dirty secret. A one-way flight from London to Vienna will discharge around 0.2 tons of CO2. Sea level predictions seem far from transparent, but a six-inch rise over the next 20 years, as some envisage, will lap at towns like Margate, Mablethorp and West Mersea. At least we’ll always have Eurostar, which tunnels 250ft below the seabed.

Teenage doomsayer Greta Thunberg might have a point. In short, you can recycle as many cereal boxes as you like, but it won’t negate environmental damage as much as reducing flying.

From the land of flygskam, or flight shame, Swedish authorities are planning a new overnight service to the European rail hub of Cologne, where morning services speed to Paris, Hamburg and Berlin. But not until 2022. If you’re lucky.

Why the delay? Airlines can introduce international routes with minimal government assistance. A decade ago EasyJet served 500 routes. Now the number exceeds 1,000. In contrast, Eurostar’s latest route to Amsterdam took years of planning and was plagued by passport faffing. Hopefully Eurostar’s rumoured expansions to Cologne and Bordeaux will come sooner.

Another issue is price. Remember EasyJet’s opening slogan? “Making flying as affordable as a pair of jeans.” The orange airline is flogging Gatwick to Vienna flights from £21.99 this February. ÖBB’s Nightjet service from Brussels costs from €59.99 in a four-person couchette to €109.99 in a private sleeper.

One solution might be government incentives for low-carbon transportation. Or tax hikes for carbon-heavy flights. (Our government has opted to flip the equation by offering airline Flybe a tax holiday instead.)

If airline taxes rise – or, heaven forbid, sea levels do – we’ll all have to ‘make a holiday out of the journey’ as we did in pre-flight days. And that might be no bad thing. Europe’s wondrous sleeper trains still offer Agatha Christie mystery on routes like Stockholm to Berlin, Budapest to Krakow and Rome to Venice.

Want all-inclusive? Try Interrail’s First Class pass, which grants four days of premier service on 33 national rail networks during a month. It costs £280 plus a small supplement for sleeper train journeys. Perhaps it’s time to get onboard.

Will you be getting on board Europe's sleeper trains? Tell us why, or why not, in the comments below.