Promotions and assignment of rural carriers

§ 3337. Promotions and assignment of rural carriers (a) The seniority status of a rural carrier commences on the day of appointment as a regular rural carrier. Upon voluntary transfer from one post office to another, or another branch of the service into the rural delivery service, the relative seniority of the transferee commences on the day he enters the rural delivery service of the office to which transfer is made. (b) A rural carrier shall be assigned by the Postmaster General to the least desirable route upon entering the service and shall rise to the more desirable routes by seniority. (c) The Postmaster General shall base promotions and preferential assignments in the rural delivery service upon seniority and ability. If ability be sufficient, seniority shall govern.