Train services across the nation are expected to be reduced again Friday as unionized workers at the state railway operator striked for the third straight day.

Subways ran by the Korea Railroad Corp. -- lines No. 1, 3 and 4, and the Gyeongui-Jungang and Bundang lines -- are expected to operate at 82 percent of the usual level, the company said.

Other passenger services will also be affected, with the KTX bullet train running at 68.9 percent of the usual level, and the Saemaeul and Mugunghwa lines operating at 58.3 percent and 62.5 percent, respectively.

Cargo services were predicted to be hit the hardest, with only 28.6 percent of services in operation.

"There were 2,322 tickets for schedules that were suspended but not canceled," a KORAIL official said. "Please make sure to check the KORAIL website or its mobile app for revised schedules and use alternative services."

Around 11,500 members of the 21,000-strong union are taking part in the labor strike with no-set deadline, according to the labor union.

The unionized workers began their strike Wednesday, demanding additional employment and wage hikes. (Yonhap)