WASHINGTON - For many here, the train derailment in Philadelphia struck an unusually personal chord. It occurred on a route so many in the capital know well.

Sen. Tom Carper (D., Del.) had been aboard Amtrak Train 188 but got off before tragedy struck. The chief of staff for Rep. Chaka Fattah (D., Pa.) disembarked at 30th Street Station minutes before the cars overturned. Sen. Robert Menendez (D., N.J.) feared briefly that his son had been a passenger.

And several members of Congress noted that a onetime colleague, former Rep. Patrick Murphy (D., Pa.), was on board when the train went off the rails. He escaped harm.

Amtrak's route from Washington to Philadelphia to New York City to Boston is a familiar conduit between work, home, and meetings for many in the political and media elite. For some, it is as much of a commuter train as a local rail line. They ride while making calls, tapping on laptops, preparing for work, or wrapping up business.

Members of Congress representing the Northeast often rush from the Capitol to the platforms at Union Station after their last votes each week. Sen. Robert P. Casey (D., Pa.) holds press conferences at 30th Street Station before boarding for the trip to Washington.

Speaking on the Senate floor Wednesday, Sen. Cory A. Booker (D., N.J.) noted that many on the ill-fated train had boarded just a half-mile from where he stood.

"They were on their way home, on their way to work, to their husbands and wives, or their children," Booker said.

The late Sen. Frank R. Lautenberg (D., N.J.) was such an Amtrak champion that his casket returned to Washington via train from New Jersey.

Perhaps the line's most famous booster, "Amtrak Joe," commuted for decades from Delaware until he moved into the vice president's quarters.

"Amtrak is like a second family to me, as it is for so many other passengers," Vice President Biden said in a statement Wednesday. "For my entire career, I've made the trip from Wilmington to Washington and back. I've come to know the conductors, engineers, and other regulars - men and women riding home to kiss their kids good night - as we passed the flickering lights of each neighborhood along the way."

President Obama said that "along the Northeast Corridor, Amtrak is a way of life for many."

The train line can take a passenger from Washington to Philadelphia in about two hours, blasting through Maryland suburbs, by Baltimore, over a sweeping vista of the Susquehanna River, and through Delaware before arriving.

The 457-mile corridor is the most traveled in North America, Booker said, handling 750,000 passengers a day. "It is a transportation lifeline, one of our main arteries."

Menendez's son, Rob, had boarded a train Tuesday night in Washington. For a time, the senator said Wednesday, he didn't know Rob's whereabouts, but ultimately learned he had taken a later train out of Union Station.

"Thankfully, he was safe," Menendez said. "Others were not so lucky."

U.S. Rep. Robert P. Brady (D., Pa.) and Fattah each said they had never seen such a disaster in their home city in their years in Congress. Brady watched news reports in his Washington office Wednesday around midday. The channel showed an image of a young Naval Academy midshipman killed in the accident.

"Look at this guy - young kid," Brady said sadly. After his first set of votes in the House, he planned to go back to Philadelphia. "I'm too itchy being here."

Rep. Ryan Costello (R., Pa.) of Chester County, had taken an Amtrak train to Washington on Tuesday. After votes Wednesday he was scheduled to board another and return home.

For now, that one will take him as far as Wilmington.