Complex sentence: The line was interrupted between Teistungen and Duderstadt from 1945 by the inner German border, operations on the line were gradually reduced until traffic ended on the last part of the line in 2001 and it finally dismantled by 2005.
Split into simpler sentences: The line was interrupted between Teistungen and Duderstadt from 1945 by the establishment of the inner German border. Operations on the line were gradually reduced until traffic ended on the last part of the line in 2001 and it finally dismantled by 2005.