Is it a formal job for college students to enter the subway?

It is not necessarily a formal job for such people to enter the subway.

Subway companies have higher requirements for academic qualifications, and regular employees are generally above undergraduate level. If they directly sign a contract with the subway company, or are marked as regular employees in the contract, they are regular employees. If they sign a contract with a third-party intermediary, it is not.

The criteria for recruiting subway staff are graduates with bachelor degree or above, major in rail transit, industry knowledge, familiarity with subway lines and distribution of stations.