The first time Liu Yu tried going to Beijing, she didn't make it very far. Police in this quaint river city in western China boarded her train just a few stops after it departed, found her in a window seat in a crowded car and demanded she disembark.

For the next four days, the officers detained her at a police station, interrogating her about her trip, she recalled. But Liu, the wife of a taxi driver and a soft-spoken mother under normal circumstances, was defiant.

She told them she was angry about a plan to revoke all taxi permits in Dazhou and force cabbies to buy new ones. Like many others, she and her husband had gone into debt and spent their life savings to buy a permit. She was going to Beijing to appeal the city's decision at the highest levels of the government.

The police officers asked: How many others were going? Who was organizing them? Liu refused to answer. They eventually gave up and released her with a warning to stay home.

Two days later, Liu was on another train to Beijing, where she joined about 100 other Dazhou cabbies and their relatives. "We carried great hope in our hearts," she said, recalling that day in December 2003. "We believed that the central government would help us, that the heavens in Beijing must be bright."

But nearly a year later, Liu and the cab drivers of Dazhou are a dejected lot, and the faith in the ruling Communist Party that brought them to Beijing has been shattered. One government agency after another has ignored their pleas, and police in the capital have herded them onto buses and shipped them home twice. Several drivers ended up spending time in jail.

The Dazhou cabbies were trying to overturn a city decision they considered unjust, using channels the party itself had endorsed. Their long, futile struggle illustrates the difficulties ordinary Chinese face when they attempt to influence even minor public policy decisions in the world's largest authoritarian system. It also shows how the myriad demands of a society enjoying growing economic and personal freedoms are testing the Communist Party's rigid political structure.

Under the leadership of President Hu Jintao, the party has said it needs to be more responsive to the public if it is to preserve its monopoly on power. At the same time, it has ruled out democratic reform and instead sought to improve governance by encouraging citizens to assert their rights via party-run courts, media and, most recently, public hearings.

But these institutions remain weak -- the cab drivers tried and failed with all three. As a result, Chinese who have grievances against local officials often take a course that is an age-old tradition in China: They shangfang, or travel to the capital for an audience with higher authorities. In ancient China, they petitioned the emperor. Today, they petition the Communist leadership.

The party uses a bureaucracy of what it calls "Letters and Visits" offices to handle these appeals, but these offices do little more than transfer complaints to local governments, collect statistics and pressure petitioners to go home. A recent study by the Chinese Academy of Social Sciences found that only 0.2 percent of all petitioners actually succeed in getting their complaints addressed.

Yet judging by the crowds camped outside Letters and Visits offices in Beijing, as well as the official statistics available, people are petitioning the party in ever-growing numbers, by the millions if not tens of millions annually. This tide reflects an increasing willingness by citizens to defend their stakes in China's rapidly changing economy and to assert rights the party has guaranteed them, at least in its rhetoric.

The story of the Dazhou cabbies is an example of what happens when such aspirations collide with reality. This account is based on multiple interviews with more than a dozen cab drivers and their relatives, most of whom expressed fear of arrest but agreed to be identified by name, as well as with several others involved in the events.

The First Blow

The cabbies of Dazhou were a diverse bunch -- laid-off workers, demobilized soldiers, rural migrants -- but they had all adapted to the economic changes sweeping China and seized an opportunity. After saving, borrowing and doing a little research, they bought cars and taxi permits in this city of 350,000 in the mountains of Sichuan province, 800 miles southwest of Beijing.

The permits, purchased from drivers getting out of the business, cost about $10,000 each, the equivalent of several years' income for most. But they were cheaper than permits in other cities and carried no expiration date. The cabbies saw a good investment, and with hard work most were earning enough to make a decent living. Many had hired others to take on shifts, and some had invested in additional cars and permits.

But then, on Nov. 20, 2003, the city announced a plan to revoke the permits and force the cabbies to buy new ones. City officials wanted to raise funds for new projects, which could boost their careers, and offered the cabbies no compensation. The plan would mean financial disaster, especially for those who had just bought permits.

The cabbies and their relatives began gathering outside city hall almost immediately to protest the decision. After a few days, the crowd had grown to hundreds, and almost all of the city's thousand-plus cabbies were on strike.

The city sent the head of its Letters and Visits bureau to address the crowd. Using a loudspeaker and standing behind rows of police, the official told the cabbies their strike was useless. He also told them to think of their permits as old shoes that couldn't be worn any more, witnesses said.

That only made the drivers angrier. "Someone in the crowd shouted, 'We'll meet tonight at 10 at the Textiles Hotel,' and hundreds of us went," recalled Yuan Ting, 24, one of the younger and most outspoken cabbies there. "We discussed what to do, and we decided to appeal for help in Chengdu," the provincial capital.

For six days in Chengdu, she and about 200 other cabbies gathered outside government buildings, standing or kneeling in the cold and rain, chanting slogans such as, "Dazhou City, return our hard-earned capital!"

Letters and Visits officials listened politely but urged the cabbies to go home. The cabbies refused. Finally, Li Xiangzhi, the mayor of Dazhou, traveled to Chengdu and met with them in a packed hotel conference room.

A tall, lanky man in a dark suit, Li defended the re-licensing plan. But one cabbie after another stood and challenged him, describing the financial losses they would suffer. Yuan, who went into the taxi business with her husband soon after they married, took the microphone, too.

"I wasn't nervous, just angry," she recalled. "I told him, 'We're all heavily in debt. Even my husband's 80-year-old grandmother borrowed money to help us to buy the permit.' "

The mayor listened for more than two hours, then signaled a willingness to compromise. According to several drivers, he put his hand on his chest and promised, "As a city mayor, I will not let you lose all the capital you have invested."

That was enough for the drivers, and city officials arranged for buses to take them back to Dazhou. Outside the hotel, the mayor told Yuan to hurry up and gather her things, calling her a "little hot pepper."

She looked up at him and shot back, "You'd better keep your word."

A Broken Promise

The strike ended when the cabbies returned home. But less than two weeks later, the mayor broke his promise. The Dazhou government announced that it was revoking the current permits and scheduled a hearing on what it described as "reform of the taxi industry."

At the session, a slender woman with apple cheeks sat in the front row, wearing a light blue coat. Her name was Liu Yu, and her husband was a cabbie. The mayor and a row of other officials sat up front. Outside, hundreds more cabbies waited in the cold, barred from entering by military police.

Liu, 37, leaned into a microphone and denounced the city's plan. "The purpose of reform is to improve people's lives, but what you are doing now will cause this industry to collapse!" she recalled saying. "Do you call this reform? If every time a government organ takes action for a certain profit and gives it a splendid label like 'reform,' how can the people survive?"

The mayor and his colleagues cut her off. But Liu took the microphone twice more, tearing apart their arguments. Unlike other cabbies, who spoke with thick Sichuanese accents, Liu commanded attention with her smooth Mandarin, and after each of her statements, the drivers broke into loud applause.

After the hearing, the cabbies decided to take their case to Beijing and made Liu one of their representatives. Their support gave her courage when police detained her on the first train and the resolve to get on the second. During the 30-hour ride, she spoke to no one, worried that she was surrounded by undercover police. "I felt as if I could be arrested at any time," she recalled. But as the train hurtled north and the air turned cooler, her spirits began to rise.

It was her first time in Beijing, and Liu was excited as the train pulled in at dawn. Nearly 100 other cabbies, including Yuan, had already arrived. Liu joined them outside the Letters and Visits office of the government's cabinet, the State Council. Finally, she thought, they were on the verge of obtaining justice.

But then the cabbies ushered Liu inside, and a plump, middle-aged official looked up from her paperwork and glared at her. "We already know your situation. Go back," Liu recalled the woman saying. "We will communicate with your local government."

Liu tried to object, but the woman cut her off and snarled: "What use is it for you to be here?"

A String of Rebuffs

Almost every morning, a throng of petitioners fills the courtyard of the State Council's Letters and Visits office and spills through a gate onto the street. They come from across China, clutching crumpled papers detailing complaints about all manner of official abuse. At night, many camp on the street or under a nearby bridge. Some have been seeking redress for years.

The scene is repeated at the Letters and Visits offices of many state ministries, all of them in out-of-the-way locations. Because the party uses Letters and Visits statistics to evaluate local officials, many provinces assign security officers to prowl outside and intercept petitioners from home. Sometimes, they persuade people to go back. Often, they just grab them off the street.

Liu and the Dazhou cabbies sought to evade these agents by renting rooms far from the office. To save money, they stayed eight to a room and two to a bed. Every morning, they trudged back to the office, lining up before dawn. Every day, they took a number, filled out a form and sent representatives inside when they were called.

And every time, the officials' answer was the same: Go back to Dazhou.

The sessions usually lasted just a few minutes. But as the days passed, more cabbies and relatives arrived, until there were 169 of them in Beijing. As the group got bigger, the officials grew anxious. One cold night, the drivers refused to leave and sat chanting slogans and singing songs of defiance in the office courtyard.

The cabbies also tried taking their case to the Transportation Ministry and other agencies, but the officials they met were all unresponsive. Then, a Letters and Visits official gave the cabbies a sealed letter he said would solve their problem and told them to return home and give it to provincial authorities.

But it was a fleeting glimmer of hope. The cabbies who delivered it said provincial officials just tossed it in a wastebasket. It was only a letter of introduction, they reported back to their colleagues in Beijing.

Down, but Not Out

By January, the cabbies were running out of money and getting desperate. They spent two subfreezing nights camped on the street. Many had not come prepared for the cold and huddled with those who had winter coats to keep warm. Some slipped into unconsciousness and were taken to hospitals. Liu broke down and wept.

One afternoon, while walking from one office to another, members of the bedraggled group found themselves on a narrow street adjacent to the Zhongnanhai compound, the headquarters of the Chinese Communist Party. Suddenly, police surrounded them. Soon, they were loaded onto three large buses. Some cabbies resisted, kicking or smashing their heads against the windows, but there were too many police.

Officers sat with cabbies on the two-day drive back home. For hours, the silence was broken only by sobbing. But as they traversed the winding, snowy roads of the Qinling Mountains, some cabbies began a morbid chant, rooting for the vehicles to tumble off a cliff. "If we die, the problem is solved!" shouted Yuan.

Liu tried to comfort the others, but she felt defeated, too. "I was thinking that when we got back, I would definitely be arrested," she recalled. "Having suffered the hardships of Beijing, I had come to a profound realization, and I was very disappointed. I didn't know where to go to find justice."

The cabbies in Dazhou tried to free their colleagues when they arrived. Some taxis attempted to cut off the buses, and one woman lay on the highway to block their way. Later, a mob of hundreds surrounded the police academy where the cabbies were taken and staged a minor riot, smashing windows and tearing down an iron gate.

Police restored order without using violence and released most of cabbies the first night. They kept Yuan and Liu and nearly a dozen of the other representatives a day longer. Then they released everyone but Liu and three other cabbies.

Over the next two weeks, the city put pressure on the cabbies to buy the new permits. Those who did so early received discounts, and those who drove with the old permits faced fines. Police released Liu after 15 days in jail, immediately after her husband agreed to pay for a new permit.

A few weeks later, Yuan called Liu and told her the cabbies were going to Beijing again. The younger woman thought someone in the capital might still help them. At the least, she said mischievously, Beijing might punish Dazhou's party leaders if the cabbies kept going to the capital.

Liu was torn about whether to go. Her mother and her mother-in-law pleaded with her to stay. Her husband offered to go in her place but couldn't find anyone to drive his cab. Then her 8-year-old son asked what would happen to him if she was imprisoned for good. Liu decided to give up the fight.

Out of Options

The cabbies' second trip to Beijing ended like the first. After a month, police forced them onto buses and took them home. Upon their return, several cabbies were detained. Yuan said police jailed her for nearly a month, releasing her at the end of March after her husband agreed to buy a new taxi permit.

By then, almost all of the cabbies had agreed to pay for the new permits. That plunged many of them deep into debt, but it raised $10 million for the city. Yu Longhai, a city spokesman, said some of the money has been used to build roads, install new street lamps and repair gas and electrical lines.

"For the benefit of a large number of people, the reform sacrificed the interests of a small group of people," he said. "Some of the cab owners were just stirring up trouble."

The cabbies did not give up. About 350 of them put $10 to $50 each into a legal defense fund. They said they used the money to hire lawyers to sue the city and pay the travel expenses of state journalists they coaxed into visiting them this past summer.

But the money was not well spent. The journalists published only two articles, neither of which had much impact. And the lawyers were too scared to pursue the cabbies' case aggressively. One refused to speak at all during a September court hearing. And when court officials challenged another to identify himself, he claimed to be a cabbie.

Researcher Zhang Jing contributed to this report.

Liu Yu, the wife of a striking cabdriver, went to Beijing for help.Liu Yu and her husband, Liu Feng, spent their life savings to buy a taxi permit in Dazhou, China. When the city decided to revoke all permits and require cabbies to buy new ones, they were among the hundreds who fought back.Yang Hong, a former truck driver, attempted to sue the government over the permit issue.Wang Yuhua became lead plaintiff in a futile lawsuit against the government.Yuan Ting was called a "little hot pepper" by Dazhou's mayor.