UPSC - Group A officers are recruited by UPSC
Civil Service Examination - Indian Railway Traffic Service (IRTS) and the Indian Railways Accounts Service (IRAS)
Combined Engineering Service - Indian Railway Service of Engineers (IRSE), Indian Railway Service of Electrical Engineers (IRSEE), Indian Railway Services of Signal Engineers (IRSSE) and Indian Railway Store Service (IRSS)
Group B officers are directly promoted from Group C.
Group C officers are recruited through the Railway Recruitment Board (RRB). The 19 Railway Recruitment Boards (RRBs) have been functioning as prime recruiting agencies for all Zonal Railways, Production Units and other extra Zonal units of the Indian Railways. Each Railway Recruitment Board is catering to the recruitment needs of the specified jurisdiction on the Railways. However, there is no regional or linguistic distinction for recruitment to any post as far as eligibility of the candidates is concerned. Any citizen of India fulfilling the recruitment criteria can compete for any post without any regional or linguistic limitations. The Group C posts include assistant station masters, drivers, motormen, guards, signal and mechanical inspectors. Here again, staff are divided into technical and non-technical staff.