Every company shall make every railroad constructed or controlled by it of one uniform gauge or width of track from end to end. When a railroad connects with or crosses another railroad, the companies owning or controlling such railroads may adopt such uniform gauge or width of track as will enable each company to pass its cars over the railroad of the other. If railroads so connecting or crossing are constructed of different gauges or widths of track, the companies controlling them may lay down, and maintain upon the whole or any portion of such railroads, additional rails so as to admit the passage of the same cars over both railroads, and also maintain and operate either or both of such railroads upon the tracks originally constructed, as is deemed expedient by the companies owning or controlling either or both of the railroads.