CHICAGO (CBS) — Eventually, riders will be able to easily update their Facebook status from deep underground on the CTA’s subways.

The CTA and Mayor Rahm Emanuel announced plans to bring 4G wireless service to the city’s subway system on the Red and Blue lines.

The CTA has 12 miles of underground subway in addition to underground passageways connecting rail lines and nearby buildings, according to a news release from the mayor’s office.

The CTA is seeking proposals from vendors to update the service, and it will be paid from the agency’s capital fund.

The existing infrastructure dates back to 2005. It supports voice services and has limited abilities to transfer data on smart phones and tablets.