This chapter shall not be construed as being in derogation of the common law, but shall be given a liberal construction, and any doubt as to the existence or extent of a power conferred on the commission by this chapter or chapters 1, 3 and 5 of this title shall be resolved in favor of the existence of the power, to the end that the commission may effectively govern and control the public utilities placed under its jurisdiction by this chapter.
T.C.A. § 65-4-106