CCTV9英语新闻：美国客运列车脱轨致至少7人遇难 或因超速2倍行驶（在线收听）

WASHINGTON, May 13 (Xinhua) -- The passenger train that derailed near the U.S. city of Philadelphia Tuesday night was traveling twice as fast as it should have been, the National Transportation Safety Board (NTSB) said Wednesday.

Rescuers work around derailed carriages of an Amtrak train in Philadelphia, Pennsylvania, on May 13, 2015. At least 7 people are dead and over 200 others hurt. 

NTSB spokesman Robert Sumwalt said at a news briefing that the train was traveling at 106 miles per hour, or 170 kilometers per hour, while the speed limit for the curve is 50 mph. The emergency brakes slowed the train from 106 mph to 102 mph before "the entire train derailed."

The black box data recorders will be sent to Washington D.C. for assessment, said Sumwalt, who added his team will also examine other details, such as the condition of the track and the train, how signals operated and "human performance."

When asked about what makes the train going at 106 mph, Sumwalt said that needed more time to find out.

Philadelphia Mayor Michael Nutter said Wednesday that the death toll of the train derailment has risen to seven, as emergency crews continued to search for more survivors and victims of the crash.

Hospitals have treated more than 200 people, at least half of whom have been released. Among the injured, 25 passengers were being treated at Temple University Hospital, including eight in critical condition, according to the hospital's medical director Herb Cushing.

Cushing said that many passengers were injured when other passengers or objects fell on them. Authorities have not ruled out the possibility of more victims from the incident.

An Amtrak passenger train was traveling from Washington, D.C. to New York when it derailed near Philadelphia in the state of Pennsylvania Tuesday night. Philadelphia Mayor Michael Nutter said that seven cars, including the engine of the train were derailed. The train was carrying 238 passengers and five crew members.

"It is an absolute, disastrous mess," Nutter said. Rescue workers are still searching at the scene to find any possible survivor.

The Federal Bureau of Investigation said that so far there is nothing to indicate the incident was an act of terrorism.

White House press secretary Josh Earnest said that the Obama administration is "hard at work," trying to figure out what caused the crash, and that their thoughts and prayers are with the families of everyone effected.

Amtrak said that because of the derailment, train service between Philadelphia and New York City remained suspended Wednesday.