For the preparations of the examination, prepare with the SCRA Mock Test Series. The one spot for preparations for any exam is the trustworthy PREP GURU App.
Some reference books for UPSC SCRA Exam:
1. Self Study Guide for SCRA by M.K Agarwal
2. Solved Papers F-2005 SCRA by Arihant Books
3. Special Class Railway Apprentices Examination by Dr. Janmejay, Dr. Arman Shukla, Abhishek Kumar
4. UPSC SCRA Special Class Railway Apprentices by R. Gupta
5. Objective General English by R. S. Aggarwal
6. UPSC E.S General Ability by G K P