Hey NYC, want to know where the best mobile data on the subway is? Try the Q. by Stacey Higginbotham @FortuneMagazine September 9, 2015, 5:00 PM EST E-mail Tweet Facebook Linkedin Share icons New York City’s ambitious effort to install Wi-Fi and cellular data access in its subway stations by 2017 is no small feat, but testing over the summer proved that efforts to make a connection have fared better in some stations and on some subway lines than on others. For example, the best line for connectivity right now is the Q, which takes riders from Coney Island in Brooklyn to Astoria in Queens. Testing by Global Wireless Solutions at 67 stations found that the best place to find Wi-Fi and mobile data was the Q, followed by the B line. If you want to turn off your mobile data (maybe you’re close to your data limit) and want to rely on Wi-Fi alone, then the stations along the B line and the A, C, and Q lines are the commutes you want. When it came to the worst connectivity overall the 4, 5, 6 trains nabbed three of the bottom five slots when it came to both cellular and Wi-Fi. The testing also found that six of the sites where the city and Transit Wireless (the company deploying the wireless network) said there would be Wi-Fi had no detectable Wi-Fi signal, which could mean that it wasn’t actually deployed yet. Speeds were pretty good, with Global Wireless finding upload speeds of 7.8 Mbps on Wi-Fi and 5.6 Mbps using the mobile network. Download speeds were capable of Netflix NFLX or YouTube streaming with 12.8 Mbps on mobile and 8.7 Mbps on Wi-Fi. The testing took place in June through July and involved an engineer traveling through the subway using Samsung Galaxy 6 smartphones and some gear in a backpack measuring both upload and download speeds on the top four U.S. networks. Subscribe to Data Sheet, Fortune’s daily newsletter on the business of technology.