All 144 CTA rapid transit stations will be equipped with surveillance cameras by the end of this month, expanding the Big Brother reach of the nation’s most extensive and integrated camera network.

By the end of this year, CTA buses and rail stations will have nearly 3,000 high-definition surveillance cameras — up from 1,800 currently. Initially, cameras will be positioned at station entrances.

Ultimately, each station will have a “full complement” of 20 cameras. And later this year, the CTA will launch a pilot program so see “whether it’s feasible to retrofit” older CTA rail cars with cameras. New 5000-series cars come equipped with cameras.

The cameras are being bankrolled, in part, by the $22.6 million in federal Homeland Security funds the CTA has received since 2006. The CTA is investing $19 million.

“If there’s something that needs a closer look, we’re able to zoom in and get a better view. The high-definition cameras help us get a very clear picture,” said CTA President Richard Rodriguez.

“As more cameras are added. You’ll be able to go through a number of different camera views from any given station …Video images provided help first-responders to assess situations and act accordingly, whether it’s a service disruption, a medical or a police emergency.”

At a news conference at the Brown Line’s Paulina Station called to mark the security “milestone,” Mayor Daley acknowledged that CTA cameras are not routinely monitored and are mostly used to identify crime suspects after-the-fact. They can also be used to assist in evacuations after major service disruptions.

But, they are sometimes used pre-emptively.

“When schools are getting out at certain locations and a large group of students from different schools are there on CTA platforms, we will use the cameras for that purpose — to make sure all the young people are safe going to and from dealing with the CTA,” the mayor said.

Daley said there is no doubt that surveillance cameras help solve crimes.

“Say someone commits a robbery, runs to the CTA trying to get on the CTA. They come through here. When they have cameras, we’ll get their pictures coming in,” he said.

“If it’s an armed robbery, a home invasion or a burglary — whatever it is. If they’re in a car driving down, a camera will pick ‘em up.”

Daley proudly proclaimed Chicago’s vast network of public and private surveillance cameras the “largest in the United States.”

Asked for a specific number, he said, “I couldn’t give you that.