Complex sentence: Network Rail published plans in 2011 to control the railway lines in Great Britain from fourteen centres within thirty years, decommissioning the remaining mechanical signal boxes, and a joint Historic Scotland and Network Rail project reviewed the signal boxes in Scotland in 2013/14.
Split into simpler sentences: Network Rail published plans In 2011 to control the lines in Great Britain from fourteen centres within thirty years, decommissioning the remaining mechanical signal boxes. A joint Historic Scotland and Network Rail project reviewed the signal boxes in Scotland in 2013/14.