A train enters a maintenance workshop of Chengdu railway section, Feb 1, 2016. [Photo/CFP]

The Spring Festival travel rush in China has been dubbed the world's largest annual migration, with more than 2.9 billion trips being made as people reunite with families to celebrate the Spring Festival, or the Lunar New Year, which falls on Feb 8 this year. About 332 million trips are expected to be made by train during the 40-day travel rush starting from January 24.

If train attendants are at the forefront of the Spring Festival travel rush, then workers maintaining the trains are not far behind.