Complex sentence: The MUNnel System is a series of underground tunnels and overhead walkways linking most major buildings on the St. John's campus which consists of four main lines: blue, yellow, orange and green.
Split into simpler sentences: The MUNnel System is a series of underground tunnels and overhead walkways linking most major buildings on the St. John's campus. The system is comprised of four main lines: blue, yellow, orange and green.