On one hand, who wouldn’t love to shower on a train? On the other, if the shower cubicle is so small that you can’t get up again when you’ve dropped the soap maybe it is not such a wonderful idea.

This year is seeing the glorious resurgence of the sleeper train around Europe, with new routes including Brussels to Prague and Graz, in Austria, to Warsaw. This month a particularly significant overnight train – from Hamburg to Stockholm – starts running. It will be a “gamechanger”, according to the rail travel expert Mark Smith.

But with a summer appointment in Stockholm, I couldn’t afford to wait until September. So I replicated the journey as best I could, to see how night train travel feels now it appears to be back. I travelled with an Interrail pass from London to Hamburg, and then headed to Malmö, from where I boarded the somewhat aged sleeper train rattling north on the same route the new EuroNight service will use.

The service, run by Sweden’s national rail operator SJ, will “get you from London to Stockholm in pretty much 24 hours”, according to Smith, who set up the much consulted Seat61.com website. It will be the “missing link” for travellers from the UK to Sweden, perhaps persuading many to take the train, rather than fly. It starts with the Eurostar from St Pancras to Brussels and then transfers to a high-speed line to Hamburg, after which the speed will drop but comfort will rise.

EuroNight covers the 670 miles from Hamburg to Stockholm in 13 hours, starting at 9pm and, stopping off in Copenhagen, and arriving in Stockholm at 10am.

SJ’s existing sleeper service from Malmö is over quickly – I managed just four hours sleep in the six-hour journey. Nevertheless, the creaking bunk bed was snug and the gentle rat-a-tat rocking was comforting.

In truth, such a journey is too short for a sleeper service, but the Malmö to Stockholm sleeper is the best facsimile for the new service. Despite Denmark’s best efforts to derail me (trains were halted throughout Zealand for three hours after an electrical fire at a critical junction box), I made it across the Øresund rail-and-road bridge from Copenhagen just in time to join the night train and its vintage, Swedish-built sleeping carriages.

The new service will use carriages mothballed by Austrian railways several years ago. With the demand-led resurrection of sleeper services across Europe, SJ has brought them out of retirement and they are being retrofitted.The train host Jeanette Andreasson, overseeing my journey, told me: “The new sleeper coaches are not new [but they are] not as old as these ones.” However, she worried that they were a bit narrower than the existing ones.

The refurb might just be skin-deep, but they will surely be better than the Malmö to Stockholm carriages. The narrowness doesn’t bode well, though. I’m small, and yet even I found it a squeeze to shower in the Swedish-built carriages, bending down to retrieve dropped soap and struggling to get up again. “You have to soap yourself all over and then you’re slippy enough not to get stuck,” laughed Andreasson.

An en suite bathroom, albeit a tiny one, is a luxury on any train, but on the new service it will be available only as a first-class option. Budget travellers can choose a seat to doze in, with the next step up being space in a six-bunk couchette (for the first few weeks the whole service will be couchette-only).

It is not clear yet whether you will be woken at night by border control guards – the staff I spoke to on the train thought that they may look after passports during the journey, but the railway company suggested other arrangements may be necessary – and the journey will end with a boxed breakfast.

Meanwhile, mine ended in the hotel opposite Stockholm Central station, where sleeper passengers can claim a buffet breakfast of cold meats and croissants. There I caught up, via Zoom, with Maja Rosén, co-founder of the We Stay on the Ground organisation that coordinates the “flight free” movement, now with chapters worldwide.

Rosén lives on an island three hours north of Stockholm and has not flown since 2008. Travel, if it has to be done at all, ought to be by train, ferry, on foot or by cycle, she says. Flying has to be curtailed, she believes, or there will not be much of a world left to see.

“We need to be cutting emissions now, but it’s also about making a statement. Pledging to go flight free is a very effective way to make people around you realise that we need to change how we live. We can’t continue with business as usual,” Rosen says. “There are so many ways to explore the world without flying.”

One of the most significant barriers is the financial cost but my journey was not as costly for the planet. According to ecopassenger.org, travelling by train to Stockholm emitted 49kg of carbon dioxide, while a plane would emit as much as 380kg per person. Not only is fuel used more efficiently, but the EuroNight train will run on renewables.

Until recently, Swedes were among the most profligate flyers on the planet. This love affair with flying is fading fast because the climate crisis is particularly noticeable in Sweden.

Travelling by train instead of flying certainly feels more virtuous. There’s even a Swedish neologism for this feeling: tågskryt – “train bragging” – or how some people, myself included, crow about their long-distance journeys by train when others fly.

Some may consider this virtue signalling. Let them. I’ll be the one lying flat on my back beneath Egyptian cotton sheets in a gently rocking sleeper carriage rolling through Schleswig-Holstein and into the night.

The EuroNight Hamburg to Stockholm service starts on 1 September.