New York City has four commuter railroads along with some railroads which are now memories. 

* Operated by Amtrak using equipment provided by the Connecticut Department of Transportation. While selected  trains do continue to Stamford, there is a Crew change at New Haven since Metro-North employees are not qualified for Shore Line East and Shore Line East employees are not qualified from New Haven to Stamford. 

For all railroads (including Amtrak), employees actually operating the train, engineer and conductor(s), must be qualified on the territory they are operating-- switches, stations, bridges, speed limits, etc.

++ This railroad is a fallen flag .A fallen flag is a railroad which has ceased operations with no successor railroad(s). While it had its own tracks, it shared much of the same right of way (Swath of land) and some stations as the New Haven Line of today's Metro- North. Metro-North never operated this line

#  This railroad is also a fallen flag. Some of the right of way is used by today's NJT system and some is planned to be reused for future NJT services