From the FDNY Operational Reference 4th Edition:
The initial response on a report of an incident (single-source) is 1-2 Engine Companies, 1-2 Truck Companies and 1 Batallion Chief. The total response for a single source is 3 Engines, 2 Trucks and one BC. On the report of a 10-75 (working fire) the response goes to 4 Engines, 2 Trucks +FAST truck (Firefighter Assist and Rescue), 2 BC's and the First-Due Rescue (at Penn would be Rescue Co. Number 1). The Division Chief will respond at his discretion normally and is assigned should it go to an "All-Hands Box" meaning all companies are working the fire. However, as seen below he is assigned on the initial response to Penn Station.
Penn Station, Box 8171, includes a Division Chief on the initial alarm would be Division 1 (D1 is Manhattan south of 34th Street), but could be Division 3 if he is closer (D3 is Between 34th St and 125th St in Manhattan and includes GCT). In addition, a Batallion Chief is sent to the Penn Station Central Command, 9th Ave and 30th St, Box 676. Box 8550 is transmitted on request for fires in the rail tunnel from Penn Station under the East River to Queens. Manhattan dispatches two engines, two ladders and one BC to 1st Ave at 30th St, and the Queens Communications Office assigns two engines, two ladders, one rescue(Rescue 4 or if out of service the closest available Rescue), and one BC to 54th Ave and 2d St in Queens. A marine company may be dispatched depending on the situation. Operations are on the Manhattan borough channel.
This is a bit off topic and all but relates to Amtrak as this shows the FDNY response to a fire or other incident at NYP.
For all you scanner people if you want the frequencies here they are:
FDNY Citywide(good if progress reports are missed as they are repeated here): (F-1) 154.430
FDNY Queens: (F-2) 154.400
FDNY Manhattan: (F-4) 154.250