This is a common crosspost for opencellid, radiocells and mozilla location.
The rapid transit (metro,subway, tube) in my city has a very good GSM, WCDMA and LTE coverage. On the stations and inside tunnels. We have 4 different real (not virtual) operators so there a lot of stations. And there are no GPS or any other GNSS coverage, of couse.
So I can’t fill the database with TowerCollector Radiobeacon or Mozilla Stumbler.
But it will be very-very coll to see on the map where you are during the trip.
Moreover, I’m dreaming about the app that will notify me when should I exit (the station before).
I’m ready to fill the database manually: to visit all stations, make records, and publish them associating according to each station.
There is also wifi in each train (wagon), but I see no reason to put it into database as it’s moving.