Section 95(95)(ii) in The Railway Protection Force Rules, 1987
(ii)Seniority of superior officers appointed to any post in a substantivecapacity shall be determined in accordance with the date of appointment tothat post in a substantive capacity and where two or more officers areappointed to a post in a substantive capacity on the same date, theirseniority shall be determined in accordance with their order of selectionfor appointment to that post.