UPDATED 11/21/11 5:50 p.m.

CHICAGO (CBS) — A move to make platforms on the CTA ‘L’ system safer is running ahead of schedule.

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As CBS 2’s Kris Habermehl reports, Mayor Rahm Emanuel announced Monday that the installation of new security cameras at CTA ‘L’ stations has been completed well ahead of time.

“They installed 1,700 cameras six weeks ahead of schedule,” he said.

Accomapnied by Chicago Transit Authority President Forrest Claypool and Chicago Police Supt. Garry McCarthy, Emanuel announced Monday morning that new cameras have been installed at the 78 CTA train stops as part of a fast-track program.

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Emanuel made the announcement at the Clinton stop on the Pink and Green lines, where surveillance cameras were credited with helping police identify and arrest a suspect who allegedly attacked and robbed a woman of her purse in an elevator a block from the station.

The same suspect was also allegedly caught on camera using a stolen credit card, which linked him to a car burglary near CTA Headquarters, which are located down the street from the Clinton stop, two weeks earlier.

As CBS 2 Chief Correspondent Jay Levine reports, police said the cameras are proven to be effective, having caught criminals in the act and cut crime on the CTA. However, it might take a while before CTA riders start to feel safer.

Public Transportation Unit Police Cmdr. John Graeber said, “the transit cameras in Chicago right now are superior to anything else in the country.”

Graeber said there has been a 40 percent increase in robbery arrests because of cameras installed on CTA train station platforms.

For example, the cameras installed this fall on the platform of the Sheridan Road Red Line station captured pictures of a young man – carrying a distinctive red backpack – pointing a sawed-off shotgun at several riders, then making off with their money and six iPhones.

“We had that shotgun within 48 hours,” Graeber said.

Police showed the photos to people who lived near the Sheridan “L” stop, which led to a name, address and cell phone number for 18-year-old Sylvester Curry, who has been charged with four counts of armed robbery.

Police Sgt. Sean Rice said “we asked him over the course of 24 hours to turn himself in. At that point, he refused and, with the assistance of the 20th District tactical team, he was located in Harvard, Illinois, at a family member’s house.”

CTA President Forest Claypool said the cameras have done more than just solving crimes.

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“In one instance, a robber was deterred when the would-be victim pointed up at the security cameras,” Claypool said.

“I haven’t noticed them at all, but I still try to keep my guard up,” Northwest Side resident Alicia Furlow said. “I think it puts a little safety out there.”

But West Loop resident Tayo Johnson said the cameras on the CTA don’t make him feel any safer.

“It doesn’t really change anything at that moment in time, like, if you’re in danger, it’s gonna happen there and then,” he said.

Ald. Anthony Beale (9th) said, “The people who commit the crimes, they’re gonna think twice before they get on the system. … And, at the same time, when people get on the system and see that Big Brother is watching, they’re gonna feel more at ease too.”

The 1,700 new cameras nearly double the number on and around CTA property.

While its clearly impossible to monitor every camera every minute – and cameras obviously won’t catch every criminal in the act – police will be able to, as they say, “go to the videotape” and track down those responsible for most crimes on the CTA.

That could, in the long run, as Beale said, make the CTA a bad bet for criminals.

In total, images from CTA surveillance cameras have helped police track down and arrest 47 people for crimes committed on or near CTA property, according to the Mayor’s office.

When Mayor Emanuel was asked if there could be a point at which there might be too many cameras, he said, “I measure it not that way, not too many. I measure it, are we giving people the assurance that they need?”

The city has pledged to install surveillance cameras on CTA platforms, in the interior areas of ‘L’ stations, in bus stops, and even on buses. Now on the verge of the busy holiday season, the extra eyes on the crowd are welcome news.

Back in July, Mayor Emanuel announced plans for 3,000 cameras in the CTA system by year’s end, along with 50 police officers who have been deployed exclusively to the CTA.

The announcement came in the wake of a wave of violent mob attacks and other incidents in the downtown area over the summer.

Habermehl emphasized that cameras or not, this is a good time to review safety precautions for public transit. Your purse should be in front, and your wallet in your front pocket with your hand on it.

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You should be aware of your surroundings and, of course, report any suspicious activity.