Currently, only U.S. Cellular offers service in the tunnels. But that will change to allow Verizon, which has far more customers nationwide than U.S. Cellular, to operate in the CTA tunnels as well, the Chicago Sun-Times reported Saturday.

"We are trying to move it along as quickly as we possibly can," Verizon spokeswoman Carolyn Schamberger told the newspaper.

The Sun-Times said CTA workers will be able to access Verizon's tunnel service by the end of August, but it was not known when all of Verizon's 67 million users will have the option of dialing up while underground in Chicago.