JUDGMENT H.N.Seth, J. Petitioner N.M. Singh whose date of birth was September 1, 1923 entered the railway service on November 11, 1947. In due course he came; to be appointed in a substantive capacity as Inspector of works which was a post in class III service. Subsequently, in the year 1961 he was, after departmental examination, given a chance 10 officiate on the gazetted post of Assistant Engineer Class II. On February 12, 1974 he was appointed to officiate as senior scale officer of the civil engineering department, North Eastern Railway, a post in class I service. At no time the petitioner was confirmed either in a class II or class I post and throughout his substantive appointment continued to be on a class III post. On May.5, 1976 the president of India, in exercise of powers under rule 2046 (h)(i) of the Indian Railway Establishment Code, Vol. II, gave three months notice to the petitioner requiring him to retire from service prematurely. Being aggrieved by the aforesaid order of the president, the petitioner has approached this Court for relief under Art. 226 of the Constitution. Learned counsel for the petitioner impugned the order dated May 5, 1976 passed by the president compulsorily retiring the petitioner from service, on following three grounds: (1) As the petitioner held a substantive appointment on a class III service post, his case was covered by rule 2046 (h) (ii) and not rule 2046 (h) (i) and such the power to compulsorily retire him from service could be exercised only after he had attained the age of 55 years i.e. after September, 1978. (2) The power under rule 2046 (h) of the Railway Establishment Code, Vol. II could be exercised only by petitioner's appointing authority and not by the President of India; and (3) There was absolutely no material before the president on the basis of which he could have come to the conclusion that it was in public interest to retire the petitioner from service. Relevant portion of rule 2046 contained in the Indian Railway Establishment Code, Vol. Relevant portion of rule 2046 contained in the Indian Railway Establishment Code, Vol. II runs thus: " (h) Notwithstanding anything contained in this rule the appointing authority shall if it is of the opinion that it is in public interest to do so have the absolute right to retire any railway servant giving him notice of not less than three months in writing or three month pay and allowance in lieu of such notice. (i) if he is in class I or class II service or post and had entered Government service before attaining the age of 35 years, after he has attained the age of 50 years. (ii) In any other case, after he has attained the age of 55 years. A perusal of the aforesaid rule enables the appointing authority to compulsorily retire a railway servant in class I or class II service after he has attained the age of 50 years, but in respect of persons in any cither class of service or post the power for such compulsory retirement can, as laid down in subclause (ii) of Clause (h) of rule 2046, be exercised only after the Railway servant has attained the age of 55 years. According to the petitioner he held his substantive appointment in class III service and he merely been asked to officiate in class II and class I services. He was a railway servant in class III service and as such his case was covered by clause (h) (ii) of rule 2046 and he could not be retired from service before attaining the age of 55 years. Case of the respondents, on the other hand, is that as at the time when the order, compulsorily retiring the petitioner from service was passed he was actually working on a class II Post, though on officiating basis. Accordingly, the petitioner was at the relevant time a railway servant in class II service and as he had entered the railway service before attaining the age of 35 years, he could be, as provided in subclause (1) of clause (h) of rule 2046, retired from service after he had attained the age of 50 years. Accordingly, the petitioner was at the relevant time a railway servant in class II service and as he had entered the railway service before attaining the age of 35 years, he could be, as provided in subclause (1) of clause (h) of rule 2046, retired from service after he had attained the age of 50 years. Crucial question, therefore, that arises for our consideration is as to what meaning should be given to the expression 'railway servant in class I or class II service or post', as used in clause (h) (i) of rule 2046 i.e. whether the expression not only covers the case of railway servants substantively appointed in class I or class II service or to class I or class II, post but also the case of a railway servant substantive appointment in class III post but who, for the time being is officiating in a class II post. The expression 'railway servant' has been denned in rule 2003 (25) of the Indian Railway Establishment Code, Vol. II as follows: "Railway servant means a person who belongs to a service or holds a post under the administrative control of the Railway Board. It also includes a person holding the post of chief Commissioner of Railways, the Financial Commissioner of Railways or a Member of the Railway Board, persons lent from 'Service or post which is not under the administrative control of the Railway Board to a service or post which is under such administrative control do not come within the scope of this definition." Generally speaking a railway servant belongs to a service and hold the post to which he has been appointed in a substantive capacity. Accordingly if a railway servant is appointed in a substantive capacity either to a class III service or to hold in such capacity a class III post, he will be described as a railway servant in class III service or post. As laid down in rule 200H of the Railway Establishment Code, Vol. II, a railway servant officiates in a post when he performs the duties of a post on which another person holds a lien or when a competent, authority appoints him to officiate in a vacant post on which no railway servant holds a lien. As laid down in rule 200H of the Railway Establishment Code, Vol. II, a railway servant officiates in a post when he performs the duties of a post on which another person holds a lien or when a competent, authority appoints him to officiate in a vacant post on which no railway servant holds a lien. It is apparent from the definition that whenever a Government servant appointed to a post belonging to a particular service is given officiating appointment he is merely asked to perform the duties of some other post which does not belong to him. When a railway servant belonging to a particular service is asked to officiate in a post on a higher service, he continues to belong to and in 'the service to which he had been appointed on a regular basis. Merely because he is asked to perform the duties on a post in a higher service, it does not mean that he belongs to or comes in that higher service itself. Accordingly the cases of railway servants who are substantive in class III service but are for the time being officiating on a class II post will be covered by rule 2046 (h) (ii) and not by rule 2046 (h) (i) of the Code. The matter may be looked at from, another angle as well. The lien of a person to hold a post comes to an end in following circumstances: (1) When he is dismissed or removed from service; or (2) He retires from service either after reaching the age of superannuation; or (3) He is compulsorily made to retire from service in accordance with rules for compulsory retirement or (4) He voluntarily retires after serving a notice in accordance with the rules applicable on the subject. The object of retiring a person compulsorily obviously is to dissociate him from the service or the post and to put an end to his lien as defined in rule 2003(14) of the Railway Establishment Code, Vol. II, i.e. his right to hold a post including a tenure post to which he has been appointed substantively. When a person officiates in another post he continues to hold his lien on the post on which he has been substantively appointed and does not acquire any right or title to the post on which he officiates. II, i.e. his right to hold a post including a tenure post to which he has been appointed substantively. When a person officiates in another post he continues to hold his lien on the post on which he has been substantively appointed and does not acquire any right or title to the post on which he officiates. The order compulsorily retiring a railway servant, in substance, is directed towards depriving him of his right to continue in the service to which he belongs substantively. In this context the expression railway servant in class I or class II service or post, as used in subclause (1) of clause (h) of rule 2046 of the Railway Establishment Code, merely means a person who has been substantively appointed to a class I or class II service or post and belongs 'to that service or post. It does not include within its ambit a person who belongs to a lower service or post but who has merely been asked to perform the duties of class I or class II service or post. The view which we have taken is in consonance with the view taken by the Delhi High; Court in Civil Writ No. 1322 of 1975 Sri K. R. Tabiliani v. Union of India (Labour & Industrial Case 463, decided on May 23, 1977). It is thus clear that the petitioners who actually belonged to a class III railway service and who was merely officiating on a post in a class II service, was not a person in class II service or post and his case is not covered by subclause (1) of clause (h) of rule 2046 which empowered the appointing authority to retire a railway servant after he attained the age of 50 years. Petitioner's case is covered by subclause (ii) of clause (h) of rule 2046 which empowers the appointing authority to retire a railway servant only after he was attained the age of 55 years. Accordingly president's order dated May 5, 1976 seeking to retire the petitioner after attaining the age of 50 years but before attaining the age of 55 years, cannot be justified under rule 2046 of the Indian Railways Establishmentt Code, Vol. II and it deserves to be quashed. In this view of the matter it is not necessary for us to express any opinion on the other two points raised by the petitioner. II and it deserves to be quashed. In this view of the matter it is not necessary for us to express any opinion on the other two points raised by the petitioner. In the result the petition succeeds and is allowed with costs. The order dated May 5. 1976 annexure II to the writ petition is quashed.