The act entitled "An Act to Amend Sections 705, 706 and 707 of the Code of 1912, Volume I, by substituting the words ‘filed in duplicate’ wherever the word ‘recorded’ occurs," approved March 10 1920 shall not affect or apply to deeds of conveyance of railroad beds, tracks and rights of way, cars, locomotive engines, rolling stock and other railway equipment, leases and mortgages or other conditional sale of, or other instruments in writing relating to, such property which were duly recorded pursuant to the law as it existed prior to March 10, 1920 and the records thereof are hereby declared to be legal and valid according to the terms of the law existing when such recordations were made.