Commuters jostle on and off their gleaming high-speed trains at Berlin's main railway station on a cold December morning, but one platform stays stubbornly empty. Finally, a grimy engine draws in, pulling carriages that look like they saw their best days in the 1980s.

It's the sleeper train from Paris, 20 minutes late. But none of the dozen passengers who tumble out with heavy bags and rucksacks seems to mind. It's the last stop on a long journey, much as it will soon be for the train itself.

German railway company Deutsche Bahn is ending the sleeper service between Paris and Berlin this week, citing unsustainable losses. The service has been running since before World War II, and used to go all the way to Moscow.

Fierce competition from budget airlines has lured passengers away from night trains that were once a mainstay of cross-border travel in Europe, explains Deutsche Bahn spokeswoman Susanne Schulz.

"Demand has dropped by 30 percent over the past decade because of the sinking cost of airline tickets," Schulz told The Associated Press.

A mid-week journey from Berlin to Paris by night train (4 bunks to a room) costs from 70 euros ($87) and takes 12 hours. A two-hour flight with one piece of checked luggage costs from 55 euros.

Along with the link to the French capital, Deutsche Bahn is ending sleeper services between Amsterdam, Prague, Basel and Copenhagen, and cutting the connection to Amsterdam from its overnight service to Warsaw.

Railway enthusiasts fear other routes could soon follow, spelling doom for Europe's night trains as a whole. Campaigners have launched petitions calling on governments and the European Union to save what they argue is an ecological and family-friendly way to travel.

The carbon footprint for the Paris-Berlin rail journey is less than half that of a flight, according to Deutsche Bahn's website. While children pay close to full fare on airlines from the age of 2, they can ride the sleeper for free until they turn 15, and only need to reserve a seat or bed.

Others evoke the romance of rail journeys, and the fact that passengers are lifted out of the bustle of daily life for the time it takes to reach their destination.

"Going from Paris to Berlin in two hours is simply too fast," says Marie-Helene, a regular on the Paris to Berlin service who declined to give her surname. "I love reading and there's plenty of time for that on the night train."

Pointing to the two big bags in front of her, she notes that budget airlines would have charged her a hefty add-on fee. "I don't like to travel light," she laughed.

"It's also perfectly viable as a business connection," insisted Jon Worth, a consultant who started taking night trains as a means of discovering Europe and now uses them to travel between meetings. "You don't need to book a night in a hotel and you wake up in the morning at your destination."

Worth believes rail firms are wilfully neglecting their sleeper services, to the detriment of travelers. "There is a demand and it would increase if night trains were managed and marketed properly by the rail companies," he said. "It's not all about competition from airlines as they would have us believe."

Deutsche Bahn says it lost 12 million euros ($15 million) last year on the night trains it's now cutting. Investing in modern rolling stock would cost millions, the company says.

That might be necessary if it wanted to tempt travelers back into its bunks, though.

As they arrive in Berlin, a group of young Mexican travelers struggle to leave the train because one of the doors is jammed shut. A grumpy train guard eventually opens the door and the four get off, blinking in the harsh station light.

How was their journey?

"I thought it would have Wi-Fi," says Alejandra Vega, one of the group. "But it was OK."