Each company, after its line of road has been located, approved and established, may so far alter such location as to change the radius of its curves, the width of its layout, the extent of depot grounds or its slopes and embankments, may straighten and improve its lines and extend its lines of sight, when such changes are approved by the Commissioner of Transportation, and may take land for additional tracks, turnouts and freight and passenger stations and for the purpose of supplying water for the use of its engines and stations. A certificate of such changes or taking, signed by the commissioner, shall be lodged for record in the town clerk’s office in the town or towns in which such changes are made or land taken.