(CNN) -- Take more trains and fewer planes. That's what Sarah Kendrew pledged to herself a few years ago. An astronomer at the Netherlands' Leiden Observatory, she travels frequently to nearby countries on business -- and prefers to not leave vapor trails in the sky when doing so.

"I've been making a conscious effort to take trains rather than fly," she told CNN, "for environmental reasons initially, but I've also found them to be much more comfortable and convenient -- so it's not really an effort anymore."

Faced with global climate change, many around the globe -- from governments to companies to individuals -- have also warmed to train travel.

Traveling by rail is on average three to 10 times less CO2-intensive compared to road or air transport, according to the UIC, a Paris-based international organization of the railway sector.

Among governments, China has been especially aggressive, spending heavily on its emerging high-speed nationwide rail network.

In December 2009 it launched a line between the cities of Wuhan and Guangzhou that cuts travel time from over 10 hours to within three, putting pressure on domestic airlines.

With an average speed of 350 kilometers per hour, the energy-efficient train is faster than its peers in Europe and Japan and makes the Acela "Express" service in the U.S. (long woeful in rail) seem more like an amusement park tram.

Meanwhile the Boston Consulting Group estimates that by 2020 passengers will be able to travel faster point-to-point by high-speed rail than by plane on nearly half of Europe's densest air routes.

Correspondingly, impressive new train stations are sprouting up around the world. There's Beijing South, for instance, which evokes traditional Chinese architecture with its upwardly curved roofs.

In London's renovated St. Pancras station -- which manages to feel Victorian yet perfectly modern -- passengers bound for Paris on Eurostar can flirt at a romantic champagne bar that's over 90 meters long and has become a city landmark in its own right.

The firms hired to design these stations and manufacture the trains have benefited enormously from rail's rising stock.

Take Montreal-based Bombardier, for instance. While its aerospace division has struggled, its train subsidiary, Bombardier Transportation, has been surging. The subsidiary promotes the green benefits of rail travel at a web site addressed, unsubtly, http://www.theclimateisrightfortrains.com/. Judging by its revenues -- they rose $254 million to $2.5 billion for the quarter ending October 2009 -- the name is justified.

Recent contracts have included $383 million from Italy's Trenitalia, $431 million from Germany's BVG, and $4 billion from the Chinese Ministry of Railways. In the latter deal, Bombardier (in a joint Chinese venture) will supply 80 trains capable of reaching 380 kilometers per hour.

Operators, too, are promoting rail's green cred. A television ad in Norway starts with animated flowers choking on car exhaust fumes and ends with customers riding contentedly with Norwegian State Railways.

"I live and work in Europe and I am seeing a lot more advertising of the use of trains as a green choice," says Melanie Francis, a climate campaigner for Greenpeace International based in Amsterdam.

When she travels home to the UK, she skips planes in favor of Eurostar, an operator that's been savvy, she adds, about promoting its green credentials.

In France, the state rail operator SNCF is running an "Eco Mobility" campaign, including solar panels that double as advertising signs.

Then there's the more subtle marketing. Book online with Germany's national railway Deutsche Bahn and your itinerary will include bar graphs showing the wasted energy and emitted particles that would have resulted if you'd taken a car or plane instead.

Cost concerns outweigh most others

But many travelers don't much care.

In a recent survey published by Eurostar, travelers in the UK were asked to select factors that were important in choosing their holiday or short break destination. "Cost of getting there" was selected seven times more than "Carbon footprint," which ranked well below other factors as well, like "Going somewhere new."

"I do sometimes fly these routes if the airfare is significantly cheaper," admits Kendrew of her business trips around Europe.

She believes the regular prices of high-speed rail should be lower to compete more effectively with airlines. Cost may be king, but "Carbon footprint" rose slightly in the survey from 2008 to 2009, suggesting the concern, however small, wasn't dampened by a recession.

"Green has remained a constant on the consumer agenda," the report concluded.

"The fact that it is undiminished by the economic downturn suggests that, while they are yet to become mainstream, environmental concerns are here to stay."

Mark Smith, who runs the rail-travel web site Seat61.com, says he gets lots of feedback from passengers citing a desire to cut their carbon footprint.

"But they almost always say this in the same breath as saying they are fed up with flying and all the airport hassle," he adds. "One factor seems to pull, the other pushes."

Green tech trains

Train technology, meanwhile, is continually improving, allowing for even greater environmental benefits over time.

From 1990 to 2005 European railways cut their CO2 emissions by 21 percent in absolute terms, according to the UIC. In May 2008, they agreed to a target of an average sector-wide cut of 30 percent in specific emissions over the 1990 to 2020 period.

Among other improvements, modern trains weigh less, have better aerodynamics, and use regenerative systems that recover energy for power generation when braking.

More important, about 80 percent of the European rail fleet already runs on electric power, as opposed to diesel, according to the UIC. This means they're ready to switch to clean electricity when it becomes available on the grid, with no separate equipment required (as opposed to cars).

In Sweden, it's already happened. SJ, the government-owned rail operator, buys only renewable electricity from hydroelectric and wind-powered sources for its trains.

"There's a great example set by Sweden," says Francis of Greenpeace. "This is the future: to power the means of transport from renewable sources."

Even in the U.S., rail is making "progress" -- even if it's more in attitudes than action at this point. Steve Winkelman, director of transportation at the Center for Clean Air Policy in Washington, D.C., says he used to get a chilly reception from government types when discussing the benefits of rail.

That's changing, he says, thanks to a variety of factors coming together, including high fuel costs, an administration serious about high-speed rail, and of course heightened environmental concerns.

"As the planet warms," he told CNN, "we're starting to thaw out here."