All railroad companies subject to the provisions of this division shall provide at all points of connection, crossing or intersection at grade, where it is practicable and necessary for the interchange of traffic, ample facilities by track connections for transferring any cars used in the regular business of their respective lines of road from their lines or tracks to those of any other railroad company whose lines or tracks may connect with, cross or intersect their own, and shall provide equal and reasonable facilities for the interchange of cars and traffic between their respective lines and for the receiving, forwarding and delivering of passengers, property and cars to and from their several lines or on freight coming over such lines; but this shall not be construed as requiring any railroad company to furnish for another railroad company its track equipment or terminal facilities without reasonable compensation. Each of said connecting lines shall be liable for and shall pay its proportionate share, to be determined by the Public Service Commission, for the building and maintenance of such tracks and switches as may be necessary to furnish the transfer facilities required in this section.