When I am quire far advanced in game Running lots of trains and over 300 vehicles game fails to auto save or manual save giving the below error

Failed to write save data to 'C:\Users\Capns\AppData\Roaming\Captain of Industry\Saves\Strategic Sanctuary\1.save': Win32 IO returned 112. Path: C:\Users\Capns\AppData\Roaming\Captain of Industry\Saves\Strategic Sanctuary…