Possible Clues:

• NYC line that stops at Yankee Stadium, familiarly
• Original NYC subway operator
• First subway line in N.Y.C
• Big Apple subway div
• NYC's first subway co
• One way to Carnegie Hall
• NY subway line past Yankee Stadium
• Subway line of NYC
• NYC commuter svc. that includes the Flushing Line
• Operator of the original N.Y.C. subway