#1.
goes to the "New 'Concourse Yards' station"
trains run to 207 St-10 Av via Yard tracks and express
goes replacing local to 168 St-Washington Heights
#2.
The S 4 St Connector was proposed a few years ago, or not...
#3.
trains run as a Rush Hour Peak Express on the Concourse line, giving it the express <Z>