A long-awaited pilot of Wi-Fi on Metra should officially launch within a month, although some riders could be sitting in a Metra car with free secret Wi-Fi right now.

Metra has decided to expand its pilot program to all 11 lines, instead of just 10, and should provide a free Wi-Fi hotspot in one car per line within a month as part of the pilot, Metra CEO Don Orseno said Wednesday.

Ten cars already have one active hotspot each. Their existence just hasn’t been announced because the technology is still being tested, officials said.

For now, riders can’t tell if they are entering a Wi-Fi car. A dome on the outside of the car holding the technology isn’t readily visible, said Jim Derwinski, Metra chief mechanical officer.

But passengers can check their Wi-Fi network icon for “Metra Wi-Fi Onboard” and access that network right now without a password, officials conceded. A few riders have stumbled upon the network’s existence, officials said.

“We’re not keeping it a secret on purpose. We want to be ready to go when we announce it,” Metra spokesman Michael Gillis said Wednesday. “We’re still working on logistics.”

After the official launch of the pilot project, the exterior of cars with active hotspots will be clearly marked, Gillis said.

Gillis cautioned that even after the pilot officially starts, the service will only provide “basic Wi-Fi,” similar to that offered in Metra’s downtown stations.

“You can check email or surf the Web,” Gillis said. “But it won’t have the bandwidth for everyone in a car to watch ‘Game of Thrones.’ ”

The 11-car pilot is costing Metra about $35,000. In 2013, a consultant estimated it would cost $72 million to install equipment to support a much more robust Wi-Fi system on every car on every line.

Unable to find a vendor who would install the technology for free, Metra is using a less expensive option of installing Wi-Fi hotspots in individual cars. If successful, more cars could be outfitted with hotspots.

A key question is whether only basic Internet functions will satisfy riders, and whether they will work seamlessly, Orseno told a group of railroad enthusiasts Wednesday.

“Will it be successful or will it crash all the time? . . . Is it financially feasible? We hope that it works. We’ll know in the next few weeks,’’ Orseno said.

Offering Wi-Fi is part of Metra’s effort to respond to customer demands, as is the installation of Wi-Fi and charging stations at its downtown stations, Orseno said. More than 80 percent of Metra riders use a smartphone, according to one 2014 survey.

Also Wednesday, Metra announced that its customers have taken more than 1 million rides using mobile tickets on the new Ventra app.

The 1 millionth ride was taken Tuesday, exactly two months after the app was launched by Metra, CTA and Pace.

For Metra in particular, mobile ticketing has been a huge technological step forward. It allows riders to buy tickets, display tickets to conductors, load transit value, monitor their accounts and access real-time transit tracker information on their cellphones.

The app so far has been used to buy 221,000 Metra tickets. Those mobile tickets have been used to pay for 1 million rides, officials said. That includes 131,000 one-way tickets; 47,300 10-ride tickets; 20,000 monthly passes; 11,500 weekend passes plus various special event or reduced-fare tickets.