See RRB NTPC examinations don't occur regularly like the SSC CGL/ SSC CHSL. Although its targetted by the GOI and Ministry of Railways to take the examination every year in order to fill the required vacancies. So technically, till now its not conducted regularly. But its hopeful that it become regular.

To know more about RRB NTPC visit the link below:

https://competition.careers360.com/articles/rrb-ntpc-exam-dates

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