An additional station serving the university will be built at NE 45th Street and Brooklyn Avenue NE as part of the Northgate Link Extension opening in 2021, approved by voters in November 2008 as part of the Sound Transit 2 (ST2) package. A groundbreaking ceremony for the project was held on March 6, 2009, at the future site of University of Washington station, marking the beginning of University Link construction. The project used three tunnel-boring machines, all sporting a cutterhead, during construction from May 2011 to May 2012. Two of the tunnel-boring machines, named "Balto" and "Togo", were manufactured by Herrenknecht in Germany and were launched from the University of Washington station south toward Capitol Hill; each machine weighed and were named after two famous Alaskan husky sled dogs from the 1925 serum run to Nome as a reference to the Washington Huskies athletic program. Another machine, named Brenda, was manufactured by Hitachi Zosen in Japan and was launched twice to complete the tunnels from Capitol Hill station to the Downtown Seattle Transit Tunnel; the machine was later refurbished and used again on the Northgate Link Tunnel from 2014 to 2016. Light rail service on the University Link Extension began on March 19, 2016. The extension opened six months earlier than scheduled, by using unused float time, and came in $200 million under the $1.9 billion budget. Cellular service in the tunnel began in August 2016 for T-Mobile customers, provided by an agreement with Mobilitie to install a distributed antenna system during the tunnel's construction. The University Link tunnel begins in Downtown Seattle at the north end of the Downtown Seattle Transit Tunnel under Pine Street at 9th Avenue near Convention Place bus station; the nearest train stop is at Westlake station, five blocks to the west. The tunnel heads northeast along Pine Street in a cut-and-cover tunnel for two blocks until the tunnel-bored segment begins at Boren Avenue underneath Interstate 5. It turns east, dipping south as far as Union Street, before completing a turn northward along Nagle Place into Capitol Hill station, located near Cal Anderson Park and Seattle Central College on Capitol Hill. Leaving the station, University Link Tunnel then turns northeast and descends at a 4.1% grade, reaching its greatest depth under Volunteer Park at below ground level, before turning northward in the Montlake neighborhood. The tunnel passes under the Montlake Cut while climbing a 4.5% grade to end at University of Washington station near Husky Stadium.