Bundled against the cold, the businessman made his way down the steps. Coming toward him in blue mittens was a middle-aged woman.
"Do you know that we're going to take a stroll this weekend?" she whispered, using the latest euphemism for the unofficial protests that have unnerved authorities in Shanghai over the past month.
Behind her, protest banners streamed from the windows of high-rise apartment blocks, signs of middle-class discontent over a planned extension of the city's magnetic levitation, or maglev, train through residential neighborhoods.
The couple checked to make sure no plainclothes police were nearby and discussed where security forces had been posted in recent days. "Did you take any photos?" the man asked. Yes, she said, promising to send them to him so he could post the evidence online.
In a minute, the exchange was over, but the news would soon be added to the steady flow of reports being posted on blogs and community bulletin boards, as well as in housing compounds along the proposed extension -- which residents contend will bring noise pollution and possibly dangerous radiation to their neighborhoods.
The sudden "strolls" by thousands of office workers, company managers, young families and the elderly in this sleek financial hub are the latest chapter in a quiet middle-class battle against government officials. The protesters are going about their mission carefully, and many speak anonymously for fear of retribution in a country that stifles dissent.
The Communist Party has a massive security apparatus that closely monitors what it views as subversive activity. The party sometimes allows public protests if they serve its political interests, such as the ouster of corrupt officials.
But the protests here have been unusual. They are led by homeowners and professionals -- people who may not previously have had much to complain to the government about but whose awareness of their individual rights has grown along with their prosperity. Police, who have routinely put down rural protests by poor farmers, have found it more difficult to intimidate an affluent, educated crowd in a major city.
The demonstrations do have at least one recent precursor, and it is one Shanghai residents acknowledge using for inspiration. In the picturesque seaside city of Xiamen, thousands of middle-class residents have managed at least temporarily to halt the construction of a $1 billion chemical factory because of environmental concerns. Demonstrators in that city, in Fujian province, relied on the Internet and cellphone text messaging to organize strolls and other opposition.
"We learned from Xiamen," said Gu Qidong, 36, a Shanghai protester and freelance sales consultant in the health-care industry. "We have no other way besides this. We once asked if we could apply for a march permit, and the police said they would never approve it."
As in Xiamen, Shanghai residents have spent countless hours researching their cause. They have posted fliers sprinkled with such phrases as "electromagnetic compatibility" and wooed residents and news media with slick PowerPoint presentations that question whether a 55-yard-wide safety buffer envisioned for each side of the rail extension would be sufficient to keep noise and vibration from reaching their apartments.
They say the existing maglev route, which takes passengers from an out-of-the-way suburban subway stop to one of the city's international airports in less than eight minutes, is a showy waste of money. When it opened four years ago, they note, the line operated at less than 20 percent capacity; after ticket prices were lowered, it ran at 27 percent capacity.
Armed with knowledge of the law, the Shanghai residents became angry that public officials had neither given proper notice of their plans for the extension nor held a public hearing. And so they decided they had no alternative but to "take a stroll" or "go shopping." They started small, and they were careful to say they did not oppose the government.
First, a small group of protesters met at a shopping center the morning of Jan. 6, shouting "Reject the maglev!" and "We want to protect our homes!" They left after an hour, regrouping later in a neighborhood near where the extension would be built.
A few days later, hundreds of people went to a mall that is popular with tourists and made an evening stop in another affected neighborhood. By Jan. 12, thousands of people were gathering at People's Square and on Nanjing Lu, both high-profile locations in downtown Shanghai, shouting "People's police should protect the people!" and "Save our homes!"
The growing boldness of the protesters has prompted city officials to emphasize that residents should find "normal" channels to vent their unhappiness. "We will forestall and defuse social tensions," Shanghai Mayor Han Zheng said in his annual government report Thursday, in what appeared to be a tacit nod to the protesters' concerns.
After each stroll, residents upload photos and videos to Chinese Web sites, which are often blocked by the government, and to YouTube, a site that isn't. The project has turned neighbors who did not know each other into close friends and allies who now compare notes and strategize.
"They can't arrest everybody," said Yao, a 58-year-old protester who asked that his full name not be used because he is a manager at a state-owned enterprise.
'We are within the law'
"We haven't done anything wrong," said Wang Guowei, 51, a manager in a Chinese-Japanese plastics venture whose family lives near the planned extension. "We always follow the Chinese constitution, we never violate the law. And in our many contacts with the police, they say we are within the law."
A victory for the protesters here does not seem as likely as the one activists achieved in Xiamen. Proud city officials hope the maglev extension will further cement Shanghai's reputation as the mainland's most advanced city when the train connects the city's two airports and the site of the 2010 World Expo.
City officials have already made some concessions. An original plan to extend the train from Shanghai to the city of Hangzhou, for example, was scrapped in May. The new extension proposal announced Dec. 29 lops almost two miles off the old plan, and one section of track would be underground. But opponents say such concessions are small.
Critics of the government plan point out that even some residents who use the train are skeptical of the usefulness of an extension.
"I'd rather see an ordinary railway connecting" Hongqiao and Pudong international airports. "It's cheap, and it's almost the same convenience," said Chen Min, 37, an airline pilot who rides the train each time he flies abroad. "Does China really need more maglev trains? Does China really need expensive things?"
Shanghai municipal officials declined requests for comment. At a news conference this week, government spokeswoman Jiao Yang said Shanghai Maglev Transportation Development Co., the Shanghai Academy of Environmental Science and the Municipal Urban Planning Administration would analyze public opinion "seriously."
Without the entire city united against the project, residents concede they are not optimistic the extension will be scrapped.
"But we must insist on our position. We require our government to respect the law, and public construction must follow a legal framework and the right procedure," said the 54-year-old businessman who asked another protester for her photos. "Our action is a way to wake up people's awareness of their civil rights."
Researcher Zhang Jie contributed to this report.