All railroads crossing any of the streets within the City shall make and maintain said crossings as wide as the street, and all space between the tracks thereof and between the main tracks and side tracks shall be properly filled, graded and leveled in such a manner as to make the entire crossing level and uniform with said tracks. Provided, that crossings on streets other than Main Street and Third and Fourth Avenues shall be maintained as the Council from time to time directs. (6-402; 1947 Code)