On the first day of service back into lower Manhattan, service between Newark and the World Trade Center has resumed after being suspended due to a power problem.

Crowded Harrison PATH platform (Twitter)

Service resumed was suspended around 10AM and was down for roughly 2 hours.

A CBS New York reporter tweets that there is a "smoky condition"  in the tunnel

Problems cropped up the first morning for NJ Transit's return on several mornings when service was restored. Over crowding caused the North Jersey Coastal Line to suspend service and shuttle buses to be set up the next morning.