WASHINGTON (AP) -- Many thousands of travelers had to scramble Wednesday after a deadly Amtrak train derailment cut off service between New York and Philadelphia, shutting down the busiest railroad in North America.

A traveler, center, waits for a bus in New York, after the Amtrak train she was scheduled to take to Washington was canceled (AP Photo/Mark Lennihan)

Amtrak warned early Wednesday that there would be no service between the two hubs, and that service elsewhere in the region would be modified. The crash has choked North America's busiest rail system, where more than 2,200 trains run on at least some of the tracks between Washington and Boston each day. Amtrak alone carried 11.4 million passengers on the Northeast Corridor in fiscal 2013, the railroad said.

"I've been standing here in a daze, trying to figure out what to do," Bill Atkins, 48, said at Penn Station in Manhattan. The attorney was trying to get home to Tysons Corner, Virginia, after a New York business trip, and didn't learn about the crash until he woke up Wednesday. "I'm going to try to fly," he decided.

But there were no flights available from LaGuardia or Kennedy, so he was thinking about taking NJ Transit as his next step. "I think I'm going to get to the Newark Airport and just stand in line."

In Washington, the electronic boards at Union Station showed all Amtrak trains to Boston and New York cancelled. Some three dozen people were waiting in line to talk to Amtrak agents.

Sisters Wilhelmina Green, 66, and Dorothy Archbold-Wright, 68, boarded a New York-bound train in South Carolina on Tuesday night and expected to arrive Wednesday morning. They were offloaded in Washington instead after the crash.

As they waited in line to talk with an agent the women said they hoped to take a bus back. Green said she felt as though they had been shuttled from one place to another without answers.

"We want to get home," she said.

At a different part of Union Station, where buses leave from, several dozen others waited to get bus tickets as television screens showed images of the derailed train.

Birgit and Hans Rosentoft were among those waiting to for a bus. The vacationers from Copenhagen had planned to take a train to New York on Thursday, but scrapped their plans to make sure they could get to New York some other way. Hans Rosentoft, 70, said he's unimpressed with how Amtrak has handled the situation so far, and surprised the company wasn't arranging alternate transportation.

"Maybe Amtrak should have a little more accident planning," he said.

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