HANGZHOU, China — China rolled out its fastest train yet yesterday and announced that the Three Gorges Dam, the world’s biggest hydroelectric project, is now generating electricity at maximum capacity — engineering triumphs that signal the nation’s growing ambitions as its economy booms.

The successes demonstrate how, after decades of acquiring technology from the west, Beijing has begun to push the limits of its new capabilities, setting the bar higher on mega-projects as it seeks to promote the image of a powerful, modern China. But many of these initiatives have come at great human and environmental cost, and some have questioned whether the country fosters a sufficiently innovative spirit to compete on the next level.

Still in the works: more nuclear power plants, a gargantuan project to pump river water from the fertile south to the arid north, and a US$32.5 billion, 820-mile (1,300-kilometer) Beijing-to-Shanghai high-speed railway that is scheduled to open in 2012.

“We are now much faster,” Railway Ministry spokesman Wang Yongping said at Tuesday’s inauguration of the super-fast line from Shanghai’s western suburb of Hongqiao to the resort city of Hangzhou. “Now other countries are hoping to cooperate with us.”

The train will cruise at a top speed of 220 mph (350 kph), making the 125-mile (200-kilometer) trip in 45 minutes.

China already has the world’s longest high-speed rail network and aims to more than double its length to 10,000 miles (16,000 kilometers) by 2020.

Chinese companies are also vying for projects overseas, including in the U.S., which leads the world in freight railway technology but has almost no high-speed rail expertise. That’s a mark of how well and quickly the technology has been adopted by Chinese companies, who have traditionally only been able to compete on price in bidding for railway and other basic infrastructure projects in the developing world.

The Three Gorges Dam has been more controversial, though the government has relentlessly touted the US$23 billion project as the best way to end centuries of floods along the mighty Yangtze and provide energy to fuel the country’s economic boom.

The water level in the vast reservoir behind it hit its peak height of 574 feet (175 meters) at 9 a.m. on Tuesday, according to project operator, the China Three Gorges Project Corp. The previous record was 567 feet (172.8 meters), set in 2008, the year the generators began operating.

In the future, the water level will be adjusted depending on flood-control needs but kept within 100 feet (30 meters) of the maximum.

While raising the water level increases the electricity production of the dam, some geologists have warned that damming up too much water in the reservoir carries a heightened risk of landslides, earthquakes and prolonged damage to the river’s ecology. As officials attempted to raise water levels in the reservoir last fall, at least one town had to evacuate dozens of residents after a hairline crack appeared on the slopes above homes.

In addition, millions have been displaced and great swaths of productive farmland sacrificed for dam and projects like it.

Company chairman Cao Guangjing called Tuesday’s feat a “historical milestone.” He said annual power generation will reach 84.7 billion kilowatt hours, enabling “the project to fulfill its functions of flood control, power generation, navigation and water diversion to the full.”

Average economic growth rates of more than 9 percent per year over the past two decades have laid the foundation for rapid progress in a growing number of fields, including launching three manned space flights since 2003 and building a railway across the Tibetan plateau from Beijing to Lhasa. The 2008 Beijing Olympics and this year’s mammoth Shanghai World Expo have demonstrated a growing managerial sophistication as well as ability to build infrastructure on an enormous scale.

But while the tremendous growth has enabled China to build big, some wonder if it can build smart — and become a source of true innovation.

Science and technology research in the country tends to be heavily topdown, laden with a stifling government bureaucracy. Many of China’s best scholars and scientists depart for greener pastures abroad, while other top minds are pushed into administrative roles, leaving them little time for research.

Although China holds the patents on the technology, design and equipment used by the CRH380 train, some in the industry question the degree to which China is justified in claiming the latest technology as its own.

“Everybody knows that a lot of the core technology is European,” Michael Clausecker, director general of Unife, the Association of the European Rail Industry, said in a recent interview.

And despite the obvious benefits high-speed railways bring, the replacement of slower lines with more expensive high-speed trains has prompted complaints from passengers reluctant to pay higher fares, especially on shorter routes.