WASHINGTON — Metro plans to put Wi-Fi in all of its subway stations by the end of the year, but the initial goal is for Metro to use the system, not riders.

An updated Customer Accountability Report says Metro is testing potential Wi-Fi service for customers between now and the summer at six stations downtown:

• Metro Center
• Gallery Place
• Judiciary Square
• Union Station
• L’Enfant Plaza
• Archives.

But the Wi-Fi at those and all other stations, to be installed by December at the latest, will at least initially be for Metro’s own engineering and operations.

Back in 2009, Metro announced a deal with the major cellphone carriers for a new system to provide cellphone service in tunnels and eventually Wi-Fi, but that deal fell apart. At the time, Metro had aimed to have congressionally mandated cell service by 2012.

Now, Metro plans to install the cables required for cellphone service in tunnels itself alongside the infrastructure needed for a new radio system. That installation is inching forward with a test stretch of about a mile on the Red Line.

Full cellphone service throughout Metro’s tunnels is projected to be years away.