Whenever the Council shall order any street, upon or across which there are any steam, electric, interurban or street railroad tracks, to be paved with asphalt, vitrified brick, stone block or other permanent pavement, any person having such tracks thereon, shall construct the roadbed of such tracks in the following manner:
All ties upon which rails are laid shall be firmly embedded in hydraulic cement concrete, or if the said person shall so elect, in ballast composed of broken stone or screened gravel, grouted as hereinafter provided. In case hydraulic cement concrete is used, it shall be composed, by volume, of not less than one (1) part Portland cement to three (3) parts sand and six (6) parts of broken stone or screened gravel. The concrete shall extend at least six (6) inches below the bottom of the ties with the top of the ties, but said concrete below the bottom of the pavement base need not extend more than three (3) inches beyond the ends of the ties. In case ballast is used it shall be composed of hard durable stone or of screened gravel, free from dust and dirt, of such sizes and so graded as to permit of thorough grouting. The ballast shall be at least six (6) inches thick below the bottom of the ties; and the space between and around the ties shall be filled in with ballast, level with the top of the ties; but said ballast need not extend more than three (3) inches beyond the end of the ties. The entire thickness of the ballast shall be thoroughly grouted with hydraulic cement mortar composed by volume of not less than one (1) part Portland cement, to three (3) parts sand; provided, however, that in case of any street ordered to be paved with asphalt, the Board may, at its discretion, grant such person special permission to use ballast without grouting, up to the level of the bottom of the base of such asphalt pavement; except, that in case such permission is granted, hydraulic or Portland cement concrete of the character herein provided, shall be laid between the ties and beneath the rails extending not less than one (1) foot on each side of each rail and not less than four (4) inches in thickness beneath the rails.