BEIJING - China's railroads and highways will see their busiest day of the Spring Festival holiday on Tuesday when the number of travelers returning to major cities hits its peak, just as a cold snap sweeps across much of the country, the ministries of railways and transport said on Monday.

The Ministry of Railways said on its website that there had been a sharp rise in the number of travelers leaving smaller cities on Monday bound for such places as Beijing, Shanghai and Guangzhou.

The ministry said the number of people on the move on Tuesday is likely to make the day the Spring Festival travel peak.

The nation's roads are also likely to be at their Spring Festival maximum on Tuesday and Wednesday, the Ministry of Transport reported on Monday on its official website.

The National Meteorological Center (NMC) added on Monday that a moderate cold snap was expected on Tuesday, causing temperatures to fall by between four and six degrees in most parts of China.

The weather pattern will bring widespread rain and snow to the southern part of China from Wednesday to Friday, the NMC said.

The Ministry of Railways said on its website that it has asked its local branches to be prepared for the upcoming icy weather.

Meanwhile, the local authorities in big cities have been bracing for the arrival of massive numbers of travelers as the Spring Festival holiday winds down.

In Shanghai, tens of thousands of public transportation workers cut their holidays short and put 27 additional bus lines on the road to meet demand as passengers began arriving in large numbers at the city's railway stations.

The influx began on Saturday night, according to local newspaper Wenhui Daily.

On Sunday, the pressure intensified on the Qinghai-Tibet railway, two days earlier than expected.

As a result, the railway company organized additional workers to facilitate the flow of people through Xining Railway Station in Northwest China's Qinghai province.

Many volunteers have also been pitching in to help keep people moving and have offered to do various jobs at stations, such as helping people buy tickets and assisting them in checking their travel schedules.

Among them, Liu Chen, a student from the Guangzhou-based Zhongkai University of Agriculture and Engineering, has been helping people at Guangzhou Railway Station by carrying their bags.

"One day, I helped more than 70 passengers with their luggage and, after all of them got on the trains, it felt like my legs were almost paralyzed," he said.

The Hohhot railway bureau in North China's Inner Mongolia autonomous region said it is expecting so many extra passengers that it has scheduled four additional trains for lines to Chongqing and Beijing.

With so many people scrambling to get back from family gatherings and holidays to their jobs in China's big cities, the rush to buy tickets has been phenomenal. Tickets for trains that will leave Nanjing on Tuesday for Beijing, Guangzhou, Harbin and Changchun had virtually all gone on Monday morning, Jiangsu's Yangtse Evening Post reported.

On Sunday, the fourth day of Spring Festival, the country's railways carried a total of 5.3 million travelers, which was up by 12.8 percent on the 4.7 million who rode the rails a day earlier, according to the Ministry of Railways.

Another 38.6 million travelers made Spring Festival trips on Sunday on buses and ships, according to the Ministry of Transport.

The traditional chunyun period, or Spring Festival travel season, runs for 40 days and is calculated in two phases: 15 days before Spring Festival Eve and 25 days after it, as stipulated by the central government.

China's railways moved about 77.3 million passengers during the first 15-day period, which ran from Jan 19 to Feb 2, the Ministry of Railways reported.