(a) Through lines for continuous service.--The commission may, upon complaint or upon its own motion, after reasonable notice and hearing, by order, require any two or more public utilities, whose lines or wires form a continuous line of communication, or could be made to do so by the construction and maintenance of suitable connections or the joint use of facilities, or the transfer of messages at common points, between different localities which cannot be communicated with, or reached by, the lines of either public utility alone, where such service is not already established or provided, to establish and maintain through lines within this Commonwealth between two or more such localities. The rate for such service shall be just and reasonable and the commission shall have power to establish the same, and declare the portion thereof to which each company affected thereby is entitled and the manner in which the same must be secured and paid. All facilities necessary to establish such service shall be constructed and maintained in such manner and under such rules, with such division of expense and labor, as may be required by the commission.

(b) Trunk line connections.--The commission may, upon complaint or upon its own motion, after reasonable notice and hearing, by order, require any one or more public utilities to connect their facilities, through the medium of suitable trunk lines, with such manual or automatic inter-communicating telephone or telegraph systems as may be wholly owned or leased by such public utilities, or by any other person or corporation. Rates for such trunk line connections and service shall be in accordance with tariffs filed with and approved by the commission.