The CTA announced Thursday it is working to bring 4G service to its underground wireless network.

The plan will offer reliable voice, data and Web service as part of the city’s goal to modernize its infrastructure, the CTA said. The city will work with telecommunication companies to update the the subways’ wireless technology, which has not been touched since 2005.

“Chicago’s world-class transit system continues to improve, including upgrading technology for the safety and comfort of the millions who commute by bus and train every week,” Chicago Mayor Rahm Emanuel said in a news release. “I am completely committed to investing in all aspects of our public transportation infrastructure, from rails to stations to wireless access, which will encourage ridership growth and economic opportunity.”

The CTA hopes to bring the service to 12 miles of underground subway on the Blue and Red lines. To keep costs down, service providers will use existing infrastructure in the update, including fiber optics, power sources and hardware equipment, according to the CTA.

Currently, the CTA leases its lines to six major wireless service providers. The agency says it earns $1.8 million through lease fees.

“This infrastructure was pioneering for the transit industry when it was installed and through this upgrade initiative, CTA looks to lead the industry once more by offering a fully-operational, 4G network across all major wireless service providers,” CTA president Forrest Claypool said in the news release.

The CTA said the project will be funded through its annual capital program, though the cost will not be determined until it works with wireless service providers.

However, the updated infrastructure will be funded through CTA’s annual capital program. It remains unclear when the service will be implemented.

— Tanner Maxwell