http://www.livetrains.com/plugins/cam/default.asp
http://www.railserve.com/RailCams/
http://www.durchgangsbahnhof.ch/cam1.htm#pic
1st and 3rd are site specific
2nd is a listing of various sites
some require JAVA
3rd is Swiss in location
some allow you to "control" the cam for 1 minute increments, I assume that this is if there is not a backlog.
I tried several variations of the search phrase "live train cams" and most are "mature" in nature...BE YE WARNED