NS on NEC

I hope this is the right forum for this and not the Amtrak or NS one. Last weekend I was railfanning Northern Delaware, steel industry in Claymont (great industrial switchers) and Wilmington. On my way back home just north of Wilmington I was on I 495 paralleling the NEC when I spotted an NS unit coal drag of empty cars heading North (East) towards Phila. I gave chase and caught up to it at Hook tower in Marcus Hook, Pa. I thought it would stop and reverse onto the industrial trackage there as I have seen NS trains do before. This one,however just roared through at a good 40 mph. I have never before seen a freight do this on this portion of the NEC so I gave chase again to see where it was heading to. Using the Industrial Highway I paralled it through Chester, just barely keeping up with it. I lost it at Eddystone as the NEC pulls off to the left at this point but he was still moving briskly when I lost sight of him. I was hoping to catch him going through one of the stations in Delaware County where I have never seen a freight but I knew I could never get ahead of him. What I'd like to know is where he was going and how he got there. How far up the corridor did he go ? To Arsenal and thence to the High Line ? Is this all that unsual a daylight movement ? Is there a connection to allow him to reverse and go south to the PE coal fired plant at Eddystone ? I'd really like to knw more about what I observed. Thanks