1. The facts in this case are shortly as follows: the petitioner joined the Bengal Nagpur Railway, sometime in 1945 in a Class III post, as Traffic Office Assistant (Office Superintendent), Road Transport Branch, Commercial Traffic Manager's Office. He was confirmed in that post in January, 1947. In 1950 he was first of all selected by the Selection Board to fill the post of Assistant Road Transport Officer, and he was selected for a second time for filling a post in Class II in the Commercial Department. What the Selection Board does is to put the approved candidates in a panel, from which officiating appointments are made, strictly according to priority. An officiating appointment may lead to the person holding the post being confirmed therein. The petitioner was first of all appointed to the post of an Assistant Road Transport Officer, which was a post sanctioned only for six months. Upon expiry of that period, he reverted to his substantive post. On the 27th July, 1951 he was promoted to the post of officiating Assistant Commercial Officer (Operating Branch). This is a Class II post (gazette). On the 14th April, 1952 the B. N. Railway merged with the East Indian Railw