Indian Railway is the largest employer in the world. To get into the railway job, you need to clear some exams conducted by Railway recruitment board.
As you have asked about the jobs available in railways, I am giving you some information, check below

Indian Railways has jobs for
Technical post
Non-technical post

There are 4 groups

Group A
Group B
Group C
Group D

Group A and Group B are the Techniacl group in which job posts are technical:

Indian Railways Personnel service
Indian Railways Traffic Service
Indian Railways Store service
Indian Railways mechanical engineer
Indian Railways Electrical engineer

For the technical group post you have to clear the civil service entrance exam conducted by UPSC department

Eligibility for the Technical service:
Educational Qualification: Bachelor degree in engineering with atleast 50% marks from any recognized university
Age limit: age must be between the 21 to 30 years
Nationality: Indian Citizen
For the Non-Technical job posts:

Ticket collector
Junior engineer
Clerk in train
Clerk of typist department
Maintainer engineer
Junior accountant assistant
Senior permanent way supervisor
Commercial clerk and others

For these posts you have to clear the RRB entrance exam under the RRB department

Eligibility for the non-technical post:
Educational Qualification: Any bachelor degree from any recognized university
Age limit: age below the 32 years
Nationality: Indian citizen