- A territory is considered connected if it has a station within its boundaries and track leading to at least one other station.
- A city is considered connected if a station's gather range includes the economic square containing the city 'marker', and if that station has track leading to at least one other station. If the station is placed properly, '(Connected)' shows up under the city name - but that indicates only that the station is close enough to the city, not that there's a rail connection anywhere else.
- Deliveries have to be to territories, not cities.
Solution (which I think most of you already found): Use territory connection tests if you need to verify that a delivery station is in the right place, and if possible make the territory visible. Use city connection tests only if you want to verify that the railway has made it to that location.