Silverliner V cars 821, 822, 823, and 824 have been traveling together at least since Wednesday, December 28. They would have been seen in sequence if 823 and 824 hadn't been flipped. 823 leads Pennsy-bound trains, while the set's other car, 713, leads Reading-bound trips, with 821 right behind it. This set has been on 6370 and 3755 on 5 or 6 of the 7 non-holiday weekdays during this time. These runs had a IV set on Thursday, December 29. I was not able to observe it on Tuesday, January 3, so I don't know what cars were used that day.
Soon you will need to be in your 60s in order to remember the 60s.