Subject to the provisions of this article, any public utility may issue bonds, or other interest bearing securities maturing at periods of more than 12 months after the date thereof, and may issue one or more classes of preferred stock which may have attached thereto warrants entitling the holder to subscribe for shares of common stock in such amounts, at such future dates, at such prices and on such terms and conditions as may be specified in the warrants. Such bonds, or other interest bearing obligations and such preferred stock also may be issued with provision therein that they may be converted into shares of common stock in such amounts, at such future dates, at such prices, and on such terms and conditions as may be specified therein.