You may build cities on gates, max 1 per gate.
A gate city's type matches all cities in its cluster. (Players may tax it for 1 resource of any of those cities. If it is destroyed, Provoke Outrage of all those city types.)
A: If a Gate Station is in a cluster with no other city, it has no type. Destroying it provokes no Outrage. Taxing it yields no resource, but it can still be taxed.
A: If transferred, your cities in gates still operate in the same way. If scrapped, your cities in gates no longer have a type, so they no longer produce resources when taxed and no longer Provoke Outrage when destroyed.