No ordinance relating to railroads or railroad crossings with streets and other public ways, or relating to the conduct, duties, service or rates of public utilities shall be repealed by virtue of the adoption of this city code or by virtue of § 1-2-1 of this chapter, excepting as this city code may contain provisions for such matters, in which case the city code shall be considered as amending such ordinance or ordinances in respect of such provisions only.