Generally the early morning hours are best. Now that the sun is coming up before 7AM it's probably best if you get trackside earlier. Yesterday morning, Saturday 4/28, I was home listening to the scanner and watching train movements on ATCS. Here's a list of the trains I heard before 9AM:
Q406 was in Philadelphia around 7AM
Q216 met Q409 at Chester around 730
Q409 met D729 at W. Feltonville at Q438 at Elsmere
Q438 met Q741, Q173, and D732 at Chester
Also thrown in that mix was Q370 working Belvidere and Q703 getting ready to come out of Philly. There was also an unidentified eastbound, presumably Q172.
http://members.trainorders.com/nanshant/csx.html
Nick