What is your favorite spot to train watch at?

Cresson, Pennsylvania on the NS Pittsburgh Sub. That will always be number 1 in my book.

Saline Hill. Man, seeing the CSX and CP action. BEA utiful

Harpers Ferry West VA. Great scenery and a good number of both freight and passenger. Plus a good bike trail for a little break from the trains

mineola ny
lots of lirr action

south station, boston
basically a lot of MBTA and a little less Amtrak

Horseshoe curve
lots of freight

I live near Philly so,
1.30th street station, amtrak, septa, NJT atlantic coast, high line and the old B&O tracks now CSX and many good vantage points like partking garages make this place great
2. trenton, lots of NJT and amtrak
3. Cornwells hights like trenton but closer to home, no NJT but Setpa
4. West Trenton, a good amount of Frieght, and septa. easy to get to because I live close to that line

Mount Washington Station (an abandoned station in Baltimore used by the B&O's Blue Commit, now used as a art studio by MICA). This is the CSX Main to Philadelphia and to the Port of Baltimore.

Landsdowne near Route 1. This is the CSX Main to Washington DC and from the Port of Baltimore. Some MARC activity on this line as well.

A street next to the Providence Station. The station is Amtrak and MBTA. And yes, the Acela express does run thru there.

Here is a link of a view of what is looks like.

http://youtube.com/watch?v=tUzCCqecM6U

Stamford, CT Lots of action hear.
Want to check out more places

Was up in Peekskill, NY this weekend and got some rail fanning in. This station is active with both Amtraks and Metro Norths

well i go with my dad,and rockingham junction in newmarket new hampshire,its pan am, downeaster,and new hampshire northcoast gravel trains.

My most visited spot is Beacon Park in Boston, but of all time it is either Scottsbluff, NE on the UP transcon, or Alliance, NE at the BNSF facility.

Woodbourne Station,Pa(CSX Trenton Line)
Cornwell Heights,Pa(Amtrak NEC)

Anywhere along the Mainline/Keystone Corridor or Hershey, Pa along the NS Harrisburg line.

In the Spring, Summer and early fall I ride to the Lincoln Park station on my bike. I always tell myself I'm only going to come home with a few spikes and I always kind up with 60 lbs. of them in a backpack on my bike rack. Trains only go thru every hour/45 mins but its a neat place to look around. In my adventures there, in a 2 mile span, I found 6 foundations for signal bridges when it used to be a 4 track main when the Erie Lackawanna operated it from Mt. View Wayne to Boonton, NJ.

The other closest main I live to is the NYS&W River Line in Butler, NJ but only a hand full of trains go thru there now since its only one track from Little Ferry to Binghamton now, including the Starucca Viaduct. But it hasn't stopped me so far. I also ride to Ridgefield Park to CP 5 occasionally to watch CSX Florida/Chicago trains, and the NYS&W SU-99 and SU-100. GREAT photo location for CSX because trains come at speeds of about 50-79 mph around a sweeping curve, perfect telephoto shot location. But somebody owns the train station there, so I ask if anyone does go to there, please be respectful. They have been very cooperative and respectful of railfans going train watching.

Raritan, NJ. See here.