Complex sentence: The Mecca Metro or Makkah Metro is a planned four-line metro system for the city of Mecca, Saudi Arabia, constructed by China Railway Construction Corporation and run by Makkah Mass Rail Transit Company (MMRTC).
Split into simpler sentences: The Mecca Metro or Makkah Metro is a planned four-line metro system for the city of Mecca, Saudi Arabia, constructed by China Railway Construction Corporation. Now, this metro is run by Makkah Mass Rail Transit Company (MMRTC).