(CBS) — When the doors of a CTA train close, how safe are you?

In just over two weeks, two women have been attacked, one brutally. Both suspects were caught, but what’s being done to prevent attacks?

CBS 2’s Mike Parker reports.

The Chicago Police Department and CTA say, despite those fears, thanks to surveillance pictures that have resulted in arrests.

Ronald Sparks, 34, was arrested early Monday after a private CTA security guard recognized him from an image that was distributed following an attempted rape over the weekend.

Some CTA riders say they want to see more security officers like that across the transit system.

Kevin Peterson helps run a CTA watchdog group, Citizens Taking Action.

“We’re asking for more security. More human-being security,” he tells Parker. “The cameras, on their own, are not doing it.”

Chicago Police Cmdr. Nancy Lipman says authorities are doing the best they can with limited resources.

“There actually are quite a few police officers out there,” she says.

CTA officials say nearly 4,000 cameras will be installed.

Police and the CTA say the cameras and police strategy have reduced violent crime on the system by more than 30 percent. Still, they advise riders to stay alert and, if you have to, get off the train and wait for the next one.