Ticket to Ride Europe introduces train stations to connect cities through routes that belong to other players. It recently became a point of debate whether stations can be used to connect cities over empty routes. Upon reviewing the rules I found them to be somewhat ambiguous.
The rules state that a station allows its owner "to use one ... of the routes belonging to another player."
Building a train station
A Train Station allows its owner to use one, and only one, of the routes belonging to another player, into (or out of) that city to help him connect the cities on his Destination Tickets.
Further along the rules state that stations can be built on a city even if it currently has no claimed routes into it.
Stations may be built on any unoccupied city, even if it currently has no claimed routes into it.
To me belonging to another player means the route must be occupied by another player. Yet stations can be built on cities that have no routes built into them.
I think the entire point of stations is to give players an opportunity to complete routes that have been taken by other players; otherwise, there should be nothing to prevent the player from building into their destinations. Allowing players to build stations on cities with no routes built into them opens the possibility to easily complete routes by placing a station without having to pay the cost of the route. This could prove decisive at the end of the game.