York station is a great place for anyone who doesnt live near the East Coast Main line Many trains can be seen such as,

East Coast-91s and 43s
XC-220-221 and the odd 43
TP-185s
Northern-158s,150 and 142

The odd 66s but you dont really get much freight if your looking for freight doncaster is your place.

Also on summer saturdays a EMT 222 does a service to york and scarborough

Personally my favourite (so far) ECML through route station. A cathedral to the living, breathing beast that is the railway system. From its high standing walls supporting a beautiful curved roof, to its wonderful curved platforms, York Station stands as a monument to the architects that designed it many years ago. A very busy station full of noise and activity, wonderful!
Parking expensive and hard to come by, best to park and ride, or go by rail. All platforms easily accessable via a footbridge over about 4 platforms. Lifts also available if needed. Plenty of refreshment bars/cafes, and toilets. The pub next door serves hot and cold food throughout the day and is linked to the booking hall by large glass doors, in the booking hall is a coffee bar and flower seller?, and Burger King and WHSmiths are in the foyer. Cash machines are also available.
All the ECML traffic passes through this station and there are lots of local/suburban services operating from here, expect to see lots of 43/91/220/221/60/66's plus as someone else mentioned preserved steam loco's are quite common. NRM is a short walk away via footbridge, and a model railway museum is situated outside the station (city side). Incorporate your visit with a look round the city centre to finish the day off, great!
Trains all day long.
My rating 9/10.