Amtrak trains began rolling on the busy Northeast Corridor early Monday, the first time in almost a week after a deadly crash in Philadelphia, and officials vowed to have safer trains and tracks while investigators worked to determine the cause of the derailment.

Amtrak resumed service along the corridor with a 5:30 a.m. southbound train leaving New York City. The first northbound train, scheduled to leave Philadelphia at 5:53 a.m., was delayed and pulled out of 30th Street Station at 6:07 a.m. Both trains arrived at their destinations about 30 minutes behind schedule.

About three dozen passengers boarded the New York-bound train in Philadelphia, and Mayor Michael Nutter was on hand to see the passengers and train off.

All Acela Express, Northeast Regional and other services also resumed.

Amtrak officials said Sunday that trains along the Northeast Corridor from Washington to Boston would return to service in “complete compliance” with federal safety orders following last week’s deadly derailment.

Amtrak President Joseph Boardman said staff and crew worked around the clock to restore service following Tuesday night’s crash that killed eight people and injured more than 200 others.

Boardman said Sunday that Amtrak would be offering a “safer service.”

In Philadelphia on Monday, Nutter stood on the platform, greeting passengers and crew members. He pulled out his cellphone and took pictures as the train rolled out.

“It’s great to be back,” said Christian Milton of Philadelphia. “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.”

Milton said he’d think about the victims and maybe say a prayer as the train navigated the curve where the derailment happened.

Tom Carberry, of Philadelphia, praised the agencies involved in restoring service.

“My biggest takeaway was the under-promise and over-deliver, and the surprise of having it come back this morning when that wasn’t expected,” Carberry said. “That was a good thing for Amtrak.”

At New York City’s Penn Station early Monday, police with dogs flanked the escalator as a smattering of passengers showed their tickets to a broadly smiling Amtrak agent and headed down to the platform.

A sign outside the train flashed “All Aboard” in red letters.

The conductor gave a broad all-clear wave, stepped inside and the train glided out of the station.

Passenger Raphael Kelly of New York, looking relaxed, said he was “feeling fine” and had “no worries.”

Kelly, who takes Amtrak to Philadelphia weekly, said with a smile that if he did have any concerns, “I have to get over it.”

Amtrak spokesman Craig Schultz said it was important to restore service, calling the Northeast Corridor “an economic engine here on the East Coast.”

Almost 20 people injured in the train crash remain in hospitals, five in critical condition. All are expected to survive.

Investigators with the National Transportation Safety Board have focused on the acceleration of the train as it approached the curve, finally reaching 106 mph as it entered the 50-mph stretch north of central Philadelphia and only managing to slow down slightly before the crash.

The Amtrak engineer, who was among those injured in the crash, has told authorities that he does not recall anything in the few minutes before it happened.

(AP)