RRB mostly recruit the Mechanical, Electrical and Civil Engineers in maximum intakes. Although as the Railway is going online and opening up different systems to get passenger friendly environment, it has recruiting a good number of CSE and ECE graduates as well in the last 5 years. So it can be beneficial but ECE don't have that much of a vacancies as its seen in case of Mechanical, Electrical and Civil Engineering.

To know more about ME visit the link below:

https://www.careers360.com/courses/mechanical-engineering-course

To know more about EE visit the link below:

https://www.careers360.com/courses/electrical-engineering-course

To know more about ECE visit the link below:

https://www.careers360.com/courses/electronics-and-communication-engineering-course

To know more about CE visit the link below:

https://www.careers360.com/courses/civil-engineering-course

I hope this answer helps. All the very best for your future endeavors!