GUIYANG -- Heavy rain for days has flooded a railway line in Zunyi City, Guizhou Province, delaying several trains, railway authorities said on Saturday.

The railway links southwest China's Sichuan Province with Guizhou Province. The flood happened at around 2 a.m. Saturday in Tongzi County, causing interruptions between Sanyuanba and Mengdu stations.

No casualties have been reported so far. Emergency workers are rushing to repair the line.

Trains were either ordered to make detours or return in response to the emergency, according to the Chengdu railway bureau.

China renewed a blue alert for rainstorms on Saturday as the torrential rain that had lashed much of the south showed few signs of weakening.

From Saturday to Sunday, heavy rain will continue in the provinces of Sichuan, Hubei, Guizhou, Hunan, Zhejiang, Jiangxi and Fujian, with precipitation expected to reach up to 90 millimeters, the National Meteorological Center said in a statement on its website.

China has a four-tier color-coded warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.