The CTA is planning to upgrade the wireless communication network in its subways and underground facilities so riders can get "reliable wireless service".
It's the next step toward providing customers with continuous mobile phone service everywhere. According to Mayor Rahm Emanuel, wireless access is important so Chicago commuters can move around the city efficiently and productively.
The CTA just started soliciting responses from wireless telecommunication companies to help build new infrastructure. The transit agency already owns and leases its subway cellular network to six major wireless providers.
The Red Line and the Blue Line already have partial underground wireless operations.
The Associated Press contributed to this report.