However, according to a female receptionist at 12306.cn headquarters on Sunday, customers are being advised not to use such browsers or plug-ins due to privacy and security concerns.

The browsers recently caused servers at Github, one of the largest code-management websites, to break down, the Mirror Evening News reported.

"The Liebao browser and the plug-ins are totally safe," said Jin at Kingsoft. "We only help customers search for ticket information, which will not affect the servers of 12306."

He added that users merely get an optimized search result.

Zhang Peng, a Beijing business consultant, bought a ticket to Jinan, capital of Shandong province, using the Qihoo 360 browser on Friday.

"I thought it was ‘game over' when the software told me there were only a dozen tickets left, and about 200 people in the line ahead of me," she said. "But just several seconds later, the magic happened.

"The software helped me jump ahead of the others and I got a ticket."

She endorsed the software, as the browser not only made her computer go faster, but also improved the entire ticket- booking experience.

"It makes up for drawbacks in the official ticket website, improving the things the official site should have done, but somehow did not," Zhang said. "For example, the browser automatically tells you how many people are waiting ahead of you when you click on a train number, so you can decide whether to change to another train or wait."

Beijing lawyer Xiao Wenbin said while the software is unfair, it may not be against the law.

The majority of migrant workers, who make up a large number of rail passengers during Spring Festival, are not familiar with the Internet and may not even know how to use such software, he said.

"Trains are part of the public transportation system and should give equal opportunity to each citizen, no matter if they can use the Internet or not," Xiao said.

Li Shikai, 25, a graduate student in environmental science at Shanghai Ocean University, plans to travel home to Kaili, in Guizhou province, for Chinese New Year in February.

On Saturday, he tried to buy the ticket for his trip returning home on Feb 8 but failed after numerous attempts. On Sunday, with the help of a special browser, it took just two minutes to get a sleeper ticket, which cost him 353 yuan ($57).

"The software really works, but for those who cannot use the Internet, that's a problem," Li said. "The ministry should keep a balanced ratio between the tickets sold online and those sold in ticketing office to ensure fairness."

Contact the writers at jinhaixing@chinadaily.com.cn and zhaoyinan@chinadaily.com.cn