Several EMU trains are neatly lined up for "health checkups" inside a maintenance depot in Tianjin at the night of Feb 1, right before the start of Spring Festival travel rush, the annual homeward journey in China, and also the world's largest human migration.

To ensure safe and punctual departure of these trains, Li Qiwei, the leader of a maintenance team, had to work overnight with more than 40 mates on his team to perform full-body examination for 28 sets of EMUs — a workload about 20 percent higher than that of a normal workday.

Li has been working at the maintenance depot after he graduated with a degree in vehicle engineering from the Dalian Jiaotong University. Eight years of diligence saw him rising from green hands to a competent group leader. He said he felt very lucky to be able to contribute to the safety operation of the bullet trains, which are reuniting millions of people with their families during the Spring Festival travel rush.