At about 5:30 a.m. at New York's Penn Station and 6 a.m. in Philly -- a half hour late -- it was all aboard again for Amtrak service between the two cities.

Philadelphia Mayor Michael Nutter was glad-handing several passengers and crew and started taking cell phone photos when the New York-bound train finally arrived.

"It's great to be back," Christian Milton of Philadelphia told The AP.

"I've never had any real problems with Amtrak. I've been traveling it for over 10 years. There's one accident in 10 years. Something invariably is going to happen somewhere along the lines. I'm not worried about it."

In New York, there was no Mayor Bill de Blasio.

Only "police with a pair of dogs flanked the escalator as a smattering of passengers showed their tickets to a broadly smiling Amtrak agent and headed down to the platform," said the AP.

A more taciturn New Yorker, Raphael Kelly, was "feeling fine" and had "no worries."

Kelly travels often to the Ciy of Brotherly Love and said, "I have to get over it."

The "it" was last Tuesday night's horrific derailment in North Philly on a notorious curved stretch of track.

Eight people died and dozens were injured when Amtrak 188, travelling at more than 100 mph -- twice the speed limit for that stretch -- went off the rails.

The U.S. Department of Transportation's Federal Railroad Administration has ordered Amtrak to install positive train control, a technology that forces trains to slow and adjusts their speeds to match speed limits.

The death curve did not have that technology.

The  FBI, meanwhile, is investigating a "grapefruit"-sized crack on the windshield as a possible contributing factor to the disaster.

CBSNews reports the trains "slowed noticeably" when taking the curve Wednesday.