Electronics and Communication Engineering

Yes,
There are a few entrance exams in railway which needs to be cleared that will get you to work in railways.

Dear Akhil, Reva University is better as your study destination. As the courses ECE & CSE are having huge scope, you can choose any one of the course based on your interest for your career development.
In Reva University, understudies of Electrical and Electronics Engineering have the adaptability to expand their horizons in electronics and communications as the curriculum is industry oriented.
And in Computer Science Engineering too, the curriculum is designed mutually by industry and academia experts which serve the students to acquire the contemporary knowledge and advanced skills.

You must have to visit counselling center for documents verification in 1st round where you can choose upgrade option for CSE in Heritage if you put CSE from Heritage upper to the ECE from IEM.

Just check the college detail in the link given here you get all the college information which you can get by your rank:
https://www.shiksha.com/b-tech/ranking/top-engineering-colleges-in-india-accepting-jee-mains/44-2-0-0-6244

I am also an ECE student. Firstly, try to list out the areas in electronics in which you feel confident.
I am providing you below course which will give you more job opportunities in top companies like Intel, Texas instruments, AMD, CISCo, IBM, etc.
Electronics circuit design, signal processing, wireless communication, optical communication, robotics,embedded systems, analog electronics, digital electronics and VLSI design.