When so required by the City Engineer, a moving contractor shall place under each dolly or wheel used in moving the building or structure, boards or planks of adequate width and strength to carry the load without being broken, to serve as a runway for such dolly or wheel during such moving along any portion of any street which has a surface other than natural soil. The moving contractor shall prevent such dolly or wheel from ever revolving on or resting on such surface except upon such board, plank or runway.