A high-speed train is about to depart from the station of Changbaishan, or Changbai Mountains, in northeast China's Jilin Province, Dec. 24, 2021. A new high-speed railway line reaching the foot of the Changbai Mountains in Jilin Province was put into operation on Dec. 24. [Photo/Xinhua]

Aerial photo taken on Dec. 2, 2021 shows a high-speed train running in a trial operation of the new railway line reaching the foot of the Changbai Mountains in northeast China's Jilin Province. A new high-speed railway line reaching the foot of the Changbai Mountains in Jilin Province was put into operation on Dec. 24. [Photo/Xinhua]

Staff members dance on a bullet train on the first operation day of the new high-speed railway line reaching the foot of the Changbai Mountains in northeast China's Jilin Province, Dec. 24, 2021. A new high-speed railway line reaching the foot of the Changbai Mountains in Jilin Province was put into operation on Dec. 24. [Photo/Xinhua]

Staff members pose for a group photo with a bullet train on the first operation day of the new high-speed railway line reaching the foot of the Changbai Mountains in northeast China's Jilin Province, Dec. 24, 2021. A new high-speed railway line reaching the foot of the Changbai Mountains in Jilin Province was put into operation on Dec. 24. [Photo/Xinhua]

Aerial photo taken on Dec. 3, 2021 shows a high-speed train running in a trial operation of the new railway line reaching the foot of the Changbai Mountains in northeast China's Jilin Province. A new high-speed railway line reaching the foot of the Changbai Mountains in Jilin Province was put into operation on Dec. 24. [Photo/Xinhua]

Aerial photo taken on Dec. 2, 2021 shows a high-speed train running in a trial operation of the new railway line reaching the foot of the Changbai Mountains in northeast China's Jilin Province. A new high-speed railway line reaching the foot of the Changbai Mountains in Jilin Province was put into operation on Dec. 24. [Photo/Xinhua]

A staff member serves a passenger on a bullet train on the first operation day of the new high-speed railway line reaching the foot of the Changbai Mountains in northeast China's Jilin Province, Dec. 24, 2021. A new high-speed railway line reaching the foot of the Changbai Mountains in Jilin Province was put into operation on Dec. 24. [Photo/Xinhua]