Concentration and transit privileges and rates may be permitted or, upon complaint or upon its own motion after due notice and hearing, may be fixed or prescribed by the Alabama Public Service Commission upon traffic that is wholly intrastate upon such basis as is just and reasonable and as will remove any unjust discrimination or undue prejudice against intrastate commerce in favor of interstate commerce, but all such privileges and rates shall be open to all shippers and consignees for a like kind of traffic under similar circumstances and conditions, and such privileges and rates shall at all times be under the supervision, regulation and control of the Alabama Public Service Commission.