Data Sources

GIS data for NYC Subway: Stations, Lines
Network model of the NY subway system: http://transit.frumin.net/trx/data/xls/network.xls
- In part, imputed from the MTA's web site: http://mta.info/nyct/service/
GIS and network model of the TRX line, and its connections to the subway system: Stations, Lines
- In part derived from GIS file of NYC Railroads: http://www.nyc.gov/html/doitt/html/eservices/eservices_gis_downloads.shtml
The 2000 Census Journey to Work Origin/Destination tables: http://www.transtats.bts.gov/Tables.asp?DB_ID=630
- This is really the amazing one. The census actually tells you the number of commuters from every census tract to every other census tract, broken down by variables such as mode of transport, time of day, race, income, etc.
GIS data for New York State census tracts: http://www.census.gov/geo/www/cob/tr2000.html
GIS data for New York's 5 boroughs: http://www.nyc.gov/html/dcp/html/bytes/districtsmetadata.shtml