Signal drops between 4/5/6 platforms aren't a carrier problem — they're a documented infrastructure gap. AT&T is the only carrier active in tunnel segments where hardware exists, and north of 59th Street the hardware isn't there at all.

The dead zone between 4/5/6 platforms isn't a phone plan problem. It's a construction gap, and the timetable for closing it north of 59th Street is still open.

Boldyn Networks — formerly Transit Wireless, the contractor that builds and operates the MTA's subway wireless infrastructure under a long-term neutral-host contract — announced March 25 that AT&T had completed between-station cellular coverage on the 4/5 lines from Borough Hall to Fulton Street and on the G line from Court Square to Hoyt-Schermerhorn Streets. The release named AT&T "the first and currently the only carrier" to go on-air in those tunnel segments.

That distinction matters. All underground stations already carry major-carrier service and Wi-Fi at the platform. The tunnels between stations are a separate engineering problem: Boldyn installs a distributed antenna system (DAS) in the tunnel bore; each carrier then separately activates its equipment on that shared infrastructure. Where Boldyn has built, AT&T has lit up. T-Mobile, Verizon, and the MVNOs riding their networks have not.

More critically: north of 59th Street on the 4/5/6, the between-station DAS hardware doesn't exist yet. Boldyn's March release flagged "4/5/6 line segments north of 59th Street" as the next phase of expansion — without a target date. That covers the full northern run of the Lexington Avenue express, through the 60s, 70s, 80s, and uptown into the Bronx.

The slow-reconnect experience at platforms — the lag after a tunnel dead zone — is a standard network handoff: the phone wakes, scans, and reregisters with the nearest antenna. The longer the dark stretch, the longer the reconnect. On the 4/5/6 north of 59th, every inter-station tunnel is dark.

Switching from a T-Mobile MVNO to AT&T would help in the sections below 59th where AT&T has activated — but north of there, no carrier has signal in the tunnels yet. The hardware comes first.