Can basic salary differ for railway employees where to report

I have small query regarding basic fixation in Indian railways, As I know junior is having higher basic than senior, Then basic stepup to be done, but as If in lower grade a person works more than 7 years and he is promoted, but in promoted post direct recruited person is working from 1 year and his basic is lower than the recent promotee, In this situation need clarification, is it correct or we can take up this issue?