Dear aspirant, through Mechanical Engineering you can get good government jobs. You will be eligible for Engineering Service Exam (ESE), PSUs, PSCs, government jobs through GATE score. Apart from this you are get RRB, JEE, SSC, UPSC, Civil Services, etc by writing exams related to these jobs.
https://www.careers360.com/question-govt-jobs-exams-for-mechanical-engineers

https://www.careers360.com/question-government-job-in-railway-for-mechanical-engineering
There links gives you more information regarding your query please go through them.
Good Luck :)