hello khyati sharma,

hello aakash saxena,

i know this is very late response for this query but i hope it will help others later.

to prepare rrb first you've to know the pattern and syllabus of the exam.it includes,

• general awareness
• logical reasoning 
• quantitative and qualitative apptitudes

the some of best recomended books publications are,

• arihant publication
• kiran publication 
• gk publication

solve previous year papers and practice mock tests.

I Hope this information will be useful to you.

if you need additional information,let us know to help you.

Thank you!!!:)