The Office of Regulatory Staff, upon order of the commission, may issue a certificate A in the following cases:

1. (1) to an applicant to operate in territory already served by any certificate holder under this chapter or any common carrier when the public convenience and necessity in such territory are not already being reasonably served by some other certificate holder or common carrier, provided such applicant propose to operate on a fixed schedule and to comply with the other provisions contained in Articles 1 to 11 of this chapter and the rules and regulations which may be made by the commission respecting holders of this class of certificates; and

2. (2) to an applicant for a certificate to operate upon a regular schedule in a territory not already served by the holder of a certificate A, when public convenience and necessity in such territory are not being reasonably served by a certificate holder under this chapter or a common carrier; provided, that when a certificate A is issued to an applicant over territory which is being served at the time such certificate is granted by the holder of a certificate B, the right of the applicant to operate under certificate A shall not begin until the expiration of the then license year of the holder of the certificate B and the holder of a certificate B shall be preferred in granting a certificate A over the route unless in the judgment of the commission it would not be in the interest of the public service.

   In either case the existence of a railroad or other motor vehicle carrier in the territory sought to be served by the applicant shall not be considered by the commission as good cause for refusing the application.