Soon, perhaps, the United States, with the world’s largest economy will also clamber on board. So far, the United States — in spite of or perhaps because of its vast size — has virtually no fast trains capable of moving swiftly enough over a long distance to compete with airplanes.

That could change over the next decade. President Barack Obama has declared high-speed rail to be a priority. He is interested, he has said, in “innovations that change the way we travel in America” through the creation of cleaner, energy-saving options. The economic stimulus package provided $8 billion toward the development of high-speed rail. Another $2.3 billion in government awards should be announced this autumn, using money from the budget.

Soon, the U.S. government will publish its first-ever national rail plan, laying out a vision for the future of freight and passenger rail. It is supposed to be released by Sept. 15, but a spokesman for the Federal Railroad Administration, Warren Flatau, said in an e-mail that Congress had recently requested an “additional level of specificity in the document,” and the agency is studying how to proceed to provide a thorough and timely report.

Right now, the only nominally high-speed option in the United States is the Acela line, which runs through the busy Northeast corridor, from Washington to Boston. The trains are capable of traveling 150 miles, or 240 kilometers, per hour. But their average speeds are far lower, because of the need to share the track with other trains and because of the large, busy metropolises along the route.

The major plans for new rail lines in the United States center on California and Florida. Both are contemplating fast trains with dedicated tracks. Peter Gertler, the high-speed rail services chairman of HNTB, an engineering and construction management company based in Kansas City, Missouri, says that Florida is likely to have a high-speed rail line operating first, perhaps by 2015. About 95 percent of the right of way has been acquired between Orlando and Tampa Bay, Mr. Gertler said. California wants to run a line from San Francisco to Los Angeles, hitting the major cities along the way, with speeds as high as 220 miles per hour. (HNTB is managing the Florida program for the state’s department of transportation and is also involved in engineering and environmental work for the California line.)

Cities in the American Midwest, like Chicago, are looking to improve their rail lines so they can support faster trains.

European and Asian companies — which have experience with high-speed trains — stand to benefit from an American rail boom, although political considerations may require substantial involvement from U.S. companies.

“I definitely see there will be some strategic partnerships with European and Asian firms,” Mr. Gertler said, adding that the United States did not currently manufacture high-speed rail vehicles.

Companies based in Japan, Germany, South Korea, Spain, France and Italy, among others, have shown interest in working on U.S. projects. As my colleague Keith Bradsher has reported from Beijing, China has offered not only to build, but also to help finance, California’s high-speed railroad.

But some companies’ home ties are already causing trouble. S.N.C.F., the French national railroad, which is interested in Florida’s high-speed rail project, is running into protests from Holocaust survivors and their families, who cite its role in taking Jews to concentration camps during World War II. The company has responded that it had no control of its operations during that time, according to The Associated Press. But the protests have gotten the attention of the governor of Florida, Charlie Crist, who on Friday ordered his secretary of transportation to review the company’s record. California has already acted: Its legislature passed a bill late last month that would require companies interested in rail contracts to disclose their wartime roles.

But the biggest question mark hovering over the future of high-speed rail in the United States is funding. The $8 billion allocated in the stimulus package is not nearly enough, particularly because it is spread across a range of projects around the country. California’s new system alone could cost $40 billion. State governments will shoulder a substantial share of the costs, and they are grappling with budget deficits.

Mr. Gertler of HNTB said that one key will be consistent spending from the federal government. He envisioned a dedicated stream of funding, like the gasoline tax, which pays for highway maintenance. “The biggest obstacle is a permanent, sustainable and secure source of funding into the future,” he said.

Another hurdle will be complaints from communities along the routes. Last week, city council officials in Palo Alto, California, adopted a resolution of “no confidence” toward the California High Speed Rail Authority.

The objections included cost concerns and lack of a business plan, as well as reduced property values, increased traffic and noise and vibrations in Palo Alto — all “with little or no benefits to us.”

As the United States struggles forward, high-speed rail seems poised for a boom around the world. China is the real hot spot: As Mr. Bradsher has reported, China has opened or plans to open 42 high-speed lines by 2012. The Chinese have recently reached out to South Africa about working on high-speed rail there. Europe, too, hopes to expand its network, with plans to connect Portugal and Spain via high-speed rail, and to enhance links between France and Spain.

Mr. Gertler predicts that after things get rolling, a bandwagon effect will take hold, even in the United States. Once people see a system up and operating, “everybody will want to develop one,” he said.