Section 2(d) in The Railway Protection Force Rules, 1987
(d)"[Principal Chief Security Commissioner] [Substituted 'Chief Security Commissioner' by Notification No. G.S.R. 140(E), dated 2.2.2018 (w.e.f. 3.12.1987)]" means an officer, not below the rank of Deputy Inspector-General, who is the head of the Force in a zonal railway or asuperior officer so appointed in the headquarters of the Director-General or in any other formation of the Force;
