If the city condemns a public utility which is operated at the time of the commencement of the condemnation proceedings as one property or one system, it shall not be necessary in the condemnation proceedings or any of the proceedings of the council to describe or treat separately the different kinds of property composing such system, but all of the property, lands, articles, franchises, and rights which comprise such system may, unless otherwise ordered by the court, be treated together as one property and an award for the whole property in one lump sum may be made by the commissioners or other body assessing the damages on condemnation. This does not prevent the city, when the plant and property are separable into distinct parts, from acquiring only such part or parts thereof as may be necessary in the public interest.