The Washington Metropolitan Area Transit Authority is getting a brief reprieve from a Congressional mandate to provide wireless service in the capital city’s Metrorail stations and tunnels.

The new proposed continuing resolution (HR 933) that would fund the government through the end of September would also extend the federal deadline to complete deployment of wireless service from all carriers until Sept. 30. The funding law currently in effect (PL 112-175) extended Metro’s deadline until the measure’s March 27 expiration.

The extension in the latest stopgap spending bill would be good news for Metro, which stands to lose $150 million in annual funding authorization if it didn’t meet the deadline.

The incentive to establish reliable wireless service in the nation’s second-busiest rapid transit system was a priority of Congress as it wrote its 2008 rail authorization (PL 110-432).

That legislation mandated Metro allow expanded wireless from all carriers to be installed in the busiest 20 stations by March 2009 — a deadline the transit operator was able to meet — and complete the work in all stations by October 2012 or risk losing federal funding. Verizon Wireless had been the only carrier to serve Metrorail, and Metro officials say building out wireless access is safety critical since emergency information is increasingly disseminated via text and data-based alerts.

But it would also be a boon for the legions of Capitol Hill staff and K Street lobbyists, ever more tethered to their smartphones.

For its part, Metro says it is doing all it can to meet the wireless mandate, but the work hasn’t been as easy as originally planned.

In an October letter to leaders of the House Oversight and Government Reform and Senate Homeland Security and Governmental Affairs committees, Metro officials said cleanup and investigation of a 2009 crash on the red line slowed efforts to deploy broader wireless coverage. They also said bringing contract workers up to speed with safety training has slowed the process.

Also complicating Metro’s installation is Powerwave Technologies Inc., a California-based company contracted to complete much of the work. Powerwave filed for Chapter 11 bankruptcy protection in January. In documents filed with the Wilmington, Del., bankruptcy court, Powerwave accused wireless carriers of failing to pay it for services rendered.

Though the extension through Sept. 30 will give Metro some breathing room on the wireless mandate, the agency still will be seeking a longer extension, probably as part of a rail authorization that Congress is due to revisit this year. In their letter to leaders sent in October, Metro advised that it did not “anticipate full coverage in the tunnels until December 2015,” though work at only three underground stations out of 47 total remained.