I created a manhattan route in the form of the M17:
M17: Serves World Trade Center/Chambers Street to West 34th Street
Stops: Via Chambers Street, Canal Street W.Houston Street, West 4th Street, Turn right to 14th Street then up 8av with the M20. Then terminates at 34 Penn Station.
Task: Assist train passengers in going to World Trade Center in times when it is re-routed to alternative route. Assist Crosstown workers in transfers.
Additional Service: Extension to 42nd street during rush hours resulting in Battery Park City/South Ferry to 42nd street/Port Authority Bus Terminal.
This has yet to be developed but it'll be more Improved.