NEW YORK • Across Asia and Europe, high-speed rail is providing a competitive alternative to air travel on the same routes, in terms of price and the all-important barometer of time.
Put that together with the environmental benefits that flow from not burning jet fuel, and staying on the ground begins to make more sense for travellers who would otherwise trudge to the airport.
Speedy trains and planes are generally competitive until travel plans extend beyond 1,000km, at which point travellers consider flying superior for time savings, according to an overview of academic research by the Journal of Advanced Transportation.
But new technologies may push that boundary in the years and decades to come.
"Travel time is critical for the competitiveness of different transport modes," researchers from Beijing's Beihang University and the University of South Florida in Tampa wrote last year, buttressing a 2014 European study that found more air service on routes for which trains take longer.
While this supports the theory that trains can supplant air travel if door-to-door time and price are equal or better, that does not turn out to be the case in reality.
In general, the advent of fast, affordable train service in China, Japan, South Korea and western Europe has eroded such preconceptions as to how airlines and railways compete.
Speedy trains and planes are generally competitive until travel plans extend beyond 1,000km, at which point travellers consider flying superior for time savings... But new technologies may push that boundary in the years and decades to come.
The entry of high-speed rail in markets dominated by airlines does not always lead to fewer available flights as there is evidence that, in many places, affordably priced train tickets actually spur new travel demand, much the way ultra-low-cost airlines in Asia, Europe and the Americas have affected bargain fares.
The new rail industry is seeing its most vibrant growth in China, which also has the world's largest high-speed network, the fastest trains and the greatest ambitions for future expansion.
One of the world's busiest routes, Beijing to Shanghai, features the new domestically built Fuxing high-speed train, now with a top allowed speed of 351kmh.
That speed increase cut the 1,247km trip to four hours and 28 minutes on a route that has about 100 million passengers annually, according to Xinhua news agency.
Japan's high-speed shinkansen, or bullet trains, date back to the 1960s and have become a staple of domestic travel, with speeds of about 320kmh, making for a 21/2 hour trip between Tokyo and Osaka.
In 2015, 910 million Chinese travelled by all forms of rail, more than twice the 415.4 million who flew, according to the journal article. The first magnetic-levitation, or maglev train, which can travel as fast as 430kmh, operates in Shanghai. Engineers are researching future maglev trains that could travel at a stunning 600kmh, an achievement that could thoroughly upend the current dynamic between air and ground travel.
Over time, Chinese airlines and high-speed trains have generally evolved so that fares and service classes are comparable, said Assistant Professor Yu Zhang, one of the journal report's authors.
In Europe, the Eurostar high-speed rail from London to Paris and Brussels served 10 million riders last year, the fourth year since it first topped that mark. Current Eurostar fares begin at £29 (S$51), down from initial fares of £79 in the system's early days.
On the other hand, after a century of neglect, transit infrastructure in the United States has more in common with the developing world than with China or Western Europe. While Asian rail systems measure their passengers in the hundreds of millions, in the US, Amtrak had only 31.3 million riders in its 2016 fiscal year.
Its fastest train, the Acela, travels on the Boston-New York-Washington corridor with a speed capability of only 241kmh.