The Chicago Transit Authority and Metra have increased security on their trains in the months following the July transit bombings in London, and Evanston police are helping out, transit officials said.

Still some passengers say the CTA can do more to protect its trains against terrorist attacks.

CTA’s measures include putting more security personnel in uniform rather than undercover. The agency is also encouraging passengers to report all suspicious activity, CTA spokeswoman Anne McCarthy wrote in an e-mail.

At the Davis El station in downtown Evanston, electronic signs tell Purple Line riders to watch their belongings at all times.

Chicago resident Nick Roghair, 32, said he doesn’t think that’s enough. Roghair rides the Purple Line through Evanston on his way to church in Winnetka. He said security is tight in downtown Chicago but largely absent in other areas.

“I’m not sure they take transit security very seriously in this city,” Roghair said. “I know we have a lot of announcements, but it’s still fairly loose.”

For years, the CTA has hired off-duty Evanston Police Department officers to ride Purple Line trains back and forth between the Howard and Linden stations. During rush hours, the officers get off the trains and patrol the Davis El and Metra stations, said EPD Deputy Chief Joseph Bellino.

The shifts run from 7 a.m. to 11 p.m. seven days a week, and there is just one officer riding the trains at any one time.