China's rail way system is feeling the strain as travelers rush home for the Mid-Autumn Festival. [File photo]

A second round of extra trains has been ordered into operation as travel numbers reach unexpected heights during the Mid-Autumn Festival travel rush, the China Railway Corporation said Sunday.

About 9.2 million passengers travelled by rail on Saturday, up 23.2 percent from the same period last year, according to CRC data.

The CRC expected a passenger increase of 12.4 percent based on data from last year during the four-day rush beginning Friday.

On Saturday alone, passenger numbers were about 8 percent higher than what the CRC predicted the previous day.

The busiest rail lines were seen in tracks operated by railway bureaus in Beijing, Shanghai and Guangzhou, which contributed to more than 43 percent of total passenger flow on Saturday.

The CRC scheduled 5,175 routine trains and added 323 extra trains to handle the surge of passenger flow on Saturday.

To prepare for continued travel peaks, the CRC planned 264 temporary trains on Sunday to carry them swiftly to their destinations.

The Mid-Autumn Festival, which will fall on Monday this year under China's lunar calendar, is the second most important holiday for families after the Spring Festival. Many Chinese go home for family reunions or travel to tourist attractions during the holiday.