After taking land for a portion of its road, a railroad corporation may vary the direction of the road in the place where such land lies, provided it does not thereby locate its road, or a part thereof, outside the limits prescribed by its act of incorporation. Before the time required by law for completing the road, such corporation shall file the location of the different parts of the road, when such variations are made, with the clerks of the respective towns where such parts are situated, who shall record the same.