Toronto's big underground "U" is moving into modern times with the TTC's impending launch of full wireless cellphone service in its subway tunnels south of Bloor.

The good news is obvious: Riders will finally be able to text and call their loved ones or colleagues to explain why they're late while trapped on the subway.

The bad news is that only Freedom Mobile customers will actually get to make use of this new, enhanced service.

BAI Canada, a communications firm hired by the TTC to install WiFi and cell service across Toronto's subway system, confirmed to CBC this week that the southern loop of Line 1, from St. George to Bloor-Yonge, is finally expected to have full cellphone service by the end of this month.

If you’re with #Freedommobile you can expect cell service on TTC Line one. That’s legit. Right now only provider who was game for the contract

— JakeOne (@SgtRenegade) May 11, 2019

The company also confirmed that Freedom Mobile (formerly known as Wind Mobile) is still the only carrier that has agreed to use their infrastructure.

TTC passengers who happen to be with Rogers, Telus or Bell — read: 90 per cent of all riders — are flat out of luck.

At least two of Canada's "big three" telecoms are reportedly refusing to sign deals with BAI to allow access to their networks on the subway system because they'd rather own the underground cellphone infrastructure.

"Bell and other Canadian carriers look forward to building the wireless infrastructure required to serve customers in the Toronto subway system, but we have been denied access to do so," said Bell Canada in a statement to CBC, echoing previous comments about its reluctance to work with BAI.

Rogers and Bell Want Their Own Wireless Network within Toronto Subway System https://t.co/9iRW3N6SUO pic.twitter.com/oJXHUxWNfC

— AppMarsh .com (@appmarshcom1) May 13, 2019

Rogers said it is "looking at opportunities" to expand their network but would "prefer partnering with other service providers to put their own cellular network in the subway."

Fair enough, but BAI has already been working on this project since 2013. The network is in place and people are more than ready for it.

For now, the vast majority of TTC riders will have to stick to the transit commission's free public WiFi network at stations — and read books, I guess, when travelling underground.