NEWARK, N.J. (CBSNewYork) — Most light rail riders in Newark had no idea that cameras on trains were recording not only video of them, but also their voices.

It’s part of an upgraded safety plan to deter crime and unruly behavior.

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As CBS2’s Meg Baker reported, the ACLU of New Jersey sees it differently.

“Monumental invasion of privacy. That’s a real concern. No warrant or legitimate reason to be recording these conversations,” Jeanne LoCicero, Deputy Legal Director, ACLU NJ said.

LoCicero said taping conversations is problematic, and that people have the right to have a private conversation with the person next to him.

“We also don’t know how long they keep recordings or what they are doing with them,” she said.

Riders at Broad Street in Newark questioned whether safety was worth giving up some of their privacy.

“I feel like it’s an invasion of privacy on conversations with someone. They can hear it, and I don’t know why they want to hear it,” Felix Pagan said.

“I mean come on, you’ve got people making terroristic threats, you got people, criminal activity, plotting things. It’s not an invasion of privacy because you are in a public place,” Byron Huart said.

CBS2 contacted NJ Transit via phone and email on Monday, but has not received a response.

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The President of the NJ Association of Railroad Passengers called it a slippery slope.

“Before going through with something like this NJ Transit ought to survey ridership to determine if they’re okay with it,” Len Resto said.

Signs are posted on most lines, but Richard Shipman questions why NJ Transit didn’t make a bigger deal to tell riders about the new safety plan.

“I think they missed an opportunity to show how they are keeping us safe,” he said.

The surveillance cost $750,000 to install on the River Lines, and $1.9-million for the Hudson-Bergen and Newark light rail trains. It was funded by a Federal Homeland Security grant.

“Good to know that if something did happen there are cameras here,” Nick Gemma said.

“I guess there is monitoring on all public transport, but we all just don’t realize it,” Lisa Okpala added.

A possible compromise mentioned Monday would be setting an audio recorder to turn on when the sound level reaches a certain volume, such as when someone screams.

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