It doesn't have to be like this. Like some secondary schools, you can also get a college diploma by correspondence. I'll find you a more detailed book.

Treatment of graduates

1. Graduates will be awarded graduation certificates of national secondary vocational schools and national vocational qualification certificates of related majors.

2. Complete the correspondence study task of Beijing Jiaotong University or Lanzhou Jiaotong University, and those who pass the examination will be awarded the graduation certificate of the corresponding school.

3. The graduation certificate obtained by graduates is registered by the national education and human resources management department and entered into the national electronic inquiry system, and the national recognition of academic qualifications.

4. The school is responsible for recommending students for employment and establishing a stable "school-enterprise cooperation mechanism" with national rail transit enterprises.