Metro has told congressional officials it has installed equipment to power cellphones at all but three of its stations -- Virginia Square, Clarendon and Court House. But that does not mean that service has been activated, or even completed, at all the remaining 44 underground stations.

Instead, riders report a spotty, inconsistent network that varies by carrier, time of day and other, less predictable variables.

"We have begun the process of activating additional stations and will continue to do so, following the completion of installation, testing and tuning of the stations," said MelanieOrtel, the team spokeswoman for the four carriers installing the service.

Metro was supposed to have all of its underground stations and connecting tunnels wired for widespread cellphone service by Oct. 16 under a 2008 $1.5 billion federal funding deal. But the transit agency wrote to Congress last week that it does not expect to finish the work until December 2015. It has rescued its funding from immediate jeopardy with an extension until March 27, while lawmakers seek a more permanent grace period.

Riders told The Washington Examiner via Twitter that many stations have no signals at all. And even the stations that got the service installed in 2009 as part of an earlier deadline on the $1.5 billion funding deal -- or have had Verizon service since the 1990s -- aren't delivering consistent signals.

One rider reported that reception on a Sprint phone works during the evening commute at Ballston, one of the stations completed in 2009, but not in the morning.

Verizon, the company that has technically had cellphone service in all underground stations since the 1990s, still has spotty service even at the stations upgraded in 2009, such as Bethesda, according to multiple riders.

Only three of the 12 underground Green Line stations have service for one rider using a Sprint phone. And other riders report trouble with AT&T, with signals showing on their phones but not actually working.

Neither the agency, nor the coalition of carriers doing the work, would provide a list or map of where cellphone service exists -- despite the recent urging of one Metro board member in the name of safety. Metro relies on email alerts, Twitter and text messages to warn riders about delays and problems, but D.C. representative Tom Downs noted that riders in some areas of the system cannot get that information because of the service gaps.

Both Metro and the carriers also have been mum to riders about blowing the congressional deadline, discussing it only in letters to lawmakers.

"Metro will communicate with our customers as milestones are reached," Metro spokeswoman Caroline Lukas said. "We remain committed to providing service in all stations as soon as possible, and this effort is expected to be completed in a matter of months, not years."