Atlanta

Atlanta is known the City in a Forest; while having nearly 50% tree cover has many benefits, it also can contribute to sprawl. In fact, Atlanta has the lowest population density of any of the 30 largest metro area in the U.S. Atlanta's metro system is fairly limited, consisting basically of two perpendicular main lines which intersect downtown. That said, it is also efficient: it has the lowest operating cost per passenger-mile of any rail system in the country. 

This expansion provides 4 new lines that go deep into the surrounding suburbs (of which there are many). Several run on rail routes that parallel the existing MARTA network, which I have used to introduce express/local service.

MARTA already provided great access to Atlanta's airport, and the expanded network also provides convenient access to the Atlanta's Amtrak station at Brookwood, plus Gainesville to the northeast. Of note, Emory University and the Centers for Disease Control & Prevention also are served by two new lines.

Lines

• MARTA
• Red: 24 miles, 19 stations
  
• Gold: 22 miles, 18 stations
  
• Green: 6 miles, 9 stations
  
• Blue: 15 miles, 15 stations
  
• New Commuter Rail
• Pink: 70 miles, 24 stations
  
• Purple: 86 miles, 26 stations
  
• Brown: 84 miles, 26 stations
  
• Cyan: 67 miles, 25 stations