UPDATED 06/03/2011 6:45 p.m.

CHICAGO (CBS) — An Amtrak train hit a Metra commuter train Friday morning at Union Station, sending as many as 12 people to area hospitals and creating delays and commuter headaches that lasted well into the evening.

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The injured included a pregnant woman who was taken to an ambulance and transported to a hospital.

Metra said all inbound and outbound train traffic on the south end of the station was halted as a result of the slow-speed collision. Buses were dispatched to 14th and Canal streets to transport passengers on inbound trains that had to be stopped as a result of the crash.

Hours later, Federal Railroad Administration officials were inspecting tracks and signals near the site of the collision near Union Station, Metra spokeswoman Meg Reile said.

“We’re not working with the same number of tracks,” Reile said. “Things are going to change around tonight.”

As CBS 2’s Mike Parker reports, that made for an aggravating environment for commuters as they crowded hot waiting rooms in hopes of getting home after the work day.

“They need to make something happen,” one commuter told him.

The saga began around 8:20 a.m. Friday, when Metra Burlington Northern Line Train No. 1242 was pulling into the station from Aurora. It was hit by Amtrak train No. 391, a Saluki line train headed for downstate Carbondale. The trains were passing under the Central Post Office in their approach to the station.

“We had a Metra train northbound. We had an Amtrak train southbound. At some point, they came in contact with each other; some kind of area where they turn in the tracks,” said fire Assistant Deputy Fire Commissioner John McNicholas.

According to Amtrak, 117 people were on board the Amtrak train and four crew members. Several passengers were hurt. The Amtrak passengers were brought back to the station and were taken to their destinations via motor coach buses.

There were about 1,500 people on the 11-car Metra train. The Metra train had originated in Aurora, and made stops at Route 59 and in Naperville and went express to Union Station, Miller said.

Metra-Amtrak Crash

A Metra train was hit by an Amtrak train Friday morning at Union Station. (Credit: John Ehrenfeld)

SLIDESHOW: Metra-Amtrak Crash

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Two cars of the Metra train were damaged after colliding with the Amtrak train. CBS 2 viewer John Ehrenfeld sent a photograph showing one of the train cars tilted to the side.

It was not known how fast the Amtrak train was moving, Metra spokesman Tom Miller said. The Metra train was also moving at the time, according to those onboard.

Numerous firefighters were seen on the platform of Track 2 at Union Station, and emergency vehicles were gathered around the train depot.

Miller called the evaucation of the train “orderly.”

LISTEN: Newsradio 780’s Nancy Harty Reports

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As of 11 a.m., it was too early to pinpoint the cause of the accident. The switches at Union Station are controlled by Amtrak, and the National Transportation Safety Board will likely probe the possibility of both switching and operator errors.

Passengers Distraught, Terrified

CBS 2’s Susanna Song arrived at Union Station just as passengers were walking out of the train. They were visibly upset, and one girl started sobbing.

One woman experienced the crash from the upper level of the double-decker Metra train.

“We’re bouncing and shaking, and swerving. It felt almost like we were going to topple over, you know, being on the top,” the woman said.

“I felt something come at us; either we derailed or banged into something, or something came at us,” another woman said. “We grabbed each other and held onto each other.”

“We would come to, like, stops and stops, until we finally came to this major stop, and everybody just flew all over the place,” a man said.

Video Taken Inside The Metra Train Passenger Al Engmark posted this video online.

Ehrenfeld said there was a “huge bang,” followed by skidding, then another bang. Then the train was halted.

Passenger Talisha McClendon said the train car behind her – Car 4 – was crushed.

“I shouldn’t say smashed. It was gone – the whole – so there are chairs or seats; it’s all caved in,” McClendon said. “You could see the steel leaning into the car.”

People were riding in Car 4 when the accident happened.

“There were people on there. What happened to them, I don’t know, but what we can see – I didn’t see anyone moaning and groaning,” she said.

But her best friend, and the woman pregnant with twins, were rushed to the hospital.

“She’s 36 weeks pregnant with twins, and she’s injured, and then there’s another young lady that rides with us – she’s a lawyer. Her back is all injured,” a passenger said.

Passengers who were not injured were instructed to get off the train. On the intercom system, doctors were asked to stay behind to help.

“In the car behind me, apparently there’s a big hole, and probably the first half of the car – the seats were all moved into the aisle, so I feel bad for whoever was in that car,” a woman said.

Passengers said the first thing that came to their minds was that the incident was an act of terrorism. Even after finding out it wasn’t, the passengers still left quite frazzled and upset.

By just after 11 a.m., both Metra and Amtrak trains were again leaving Union Station. Earlier, all service had been stopped.

Metra has said they expect trains to be moving as normal again by the afternoon rush hour, but it’s not clear what the overall impact of the accident will be.

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The Sun-Times Media Wire contributed to this report.