TUESDAY NIGHT'S fatal derailment was the worst Philadelphia train disaster in decades. The timing seemed chillingly prophetic: Just one day before the crash, the city's Office of Emergency Management had held a "mass casualty workshop" with police, fire and health personnel.

Moments after Train 188 careened off the tracks, emergency calls went out across the city and scores of first responders rushed to the scene to find the mangled bodies of those killed and more than 200 injured and bloodied passengers.

Here's a look at how the city's response unfolded throughout Tuesday night and into yesterday:

9:21 p.m., Tuesday. Amtrak Train 188, a Northeast regional train that originated in Washington, D.C., bound for New York City, derails at 106 mph on a curve with a speed limit of 50 mph at Frankford Junction; 9-1-1 calls quickly follow.

9:39 p.m. Mayor Nutter receives a call at his Wynnefield home from Samantha Phillips, director of the city's Office of Emergency Management. Around that time, the Emergency Operations Center, housed within Fire Department headquarters on Spring Garden Street near 3rd, is activated. A mobile "command post" is also activated. Nutter jumps on the phone with chief of staff Everett Gillison, who is also deputy mayor of public safety. They discuss an immediate plan of action.

10 p.m. Nutter arrives at the crash site, where he is met by Phillips and Gillison, along with Police Commissioner Charles Ramsey, Deputy Fire Department Commissioner Jesse Wilson, city Managing Director Rich Negrin and Director of Public Safety Michael Resnick. Fire Commissioner Derrick Sawyer, who was out of town, begins to make plans to fly home.

11 p.m. Dozens of firefighters and paramedics are on the scene, using ladders to scale tipped over train cars and reach windows to rescue passengers. The Fire Department had issued a four-alarm bell. Throughout the night and morning, more than 200 people are transported and treated at hospitals. Responders took the most seriously injured to Temple University Hospital.

12:41 a.m., yesterday. The city's Office of Emergency Management sends out its first derailment-related tweet, urging people to call an Amtrak hotline for information about passengers.

12:44 a.m. A "family assistance center," where family and friends of those injured await news, is up and running at Webster Elementary School on Frankford Avenue near Ontario Street.

12:46 a.m. More than 200 Philadelphia police officers are already on the scene helping victims and assisting the Fire Department.

1:33 a.m. Emergency workers, wearing orange safety vests and carrying flashlights, continue to search grassy areas for victims thrown from train cars.

2:55 a.m. Multiple light towers and portable light units are on site to help first responders scour the area for victims.

3 a.m. Investigators with the National Transportation Safety Board begin to arrive from Washington, and federal officials work with local Red Cross and Amtrak employees to help passengers, who were newly released from the hospital and transported to 30th Street Station.

6:21 a.m. Emergency workers bring in heavy equipment, including a cherry-picker lift and crane to hoist pieces of wreckage in search of victims.

2:25 p.m. Nutter, in his second press conference of the day, confirms seven fatalities.