Beijing launched an hourly updated online index of crowds at major tourist sites on Sunday, the day that China's railway broke its record for the amount of passengers carried on any single day of a May Day holiday.

The index, launched at bjta.gov.cn on Sunday, the first day of the holiday, covers six major sites in Beijing, including the Palace Museum, Summer Palace and Badaling section of the Great Wall. It indicates the size of crowds according to a five-level system, with level five being the most crowded.

The Palace Museum, which had the more visitors than the other sites on Sunday - 10,100 people, or 26 percent more than the same day last year - was labeled level four.

"There were so many people at the Palace Museum that we just moved forward with the crowd step by step," said Joaquin Couchot, an 18-year-old exchange student from Chile, who came to Beijing with his four friends for the first time.

"The buildings are magnificent, but I didn't expect that crowd. I should have taken my Chinese friends' advice about visiting on a normal weekend," he said loudly, to be heard above the crowd.

Most tourists hadn't heard of the index. Liu Jing, a postgraduate student at Peking University, said she and her friend wanted to go boating at the Summer Palace on Sunday but the lines were just too long.

"We bought the tickets from scalpers, though they charged an extra 5 yuan (80 cents). The multitude lined up in front scared me," she said.

However, Liu suggested that the index might not deter tourists from visiting heavily crowded sites. "Visitors come here with an awareness of the large crowds, and they may not have a chance to come at another time. So they have little choice but to squeeze into the throng of people visiting the sites."

More than 1 million people visited 24 sites in Beijing on Monday, 2.9 percent more than the same day last year, according to the Beijing Travel Committee. On Sunday, those sites had 675,000 visitors.

Beijing is ranked third in the top 10 list of Chinese tourist destinations during the three-day May Day holiday, according to a report released by the China Tourism Academy and ctrip.com, a travel information website, in late April.

The report - based on hotel and flight reservations, Web surfing and searches and online surveys - said coastal cities such as Sanya in Hainan province and Xiamen in Fujian province are the most attractive for tourists and will get the most visitors. Shanghai, Hangzhou, in Zhejiang province, and Jiuzhaigou, in Sichuan province, are also in the top 10.

China's railways carried 8.2 million passengers on Sunday, according to Xinhua News Agency, more than any other single day in a May Day holiday.

Shanghai saw more rail passengers than anywhere else in China: 1.55 million, 18 percent of the Chinese rail passengers that day.

The Ministry of Transportation predicted on Friday that the railway network would carry around 31.1 million passengers during the holiday, 2.42 million more than in 2011.

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