Until now, all stations were either terminal stations or through station. However, there is often a need to have a station combining both parts, so that certain trains turn around and others do not. In these example stations, only trains entering from the bottom left will be able to reverse, but it is easily possible to change the design so that reversing is possible for both directions.
Turning around allowed
The first part are layouts which only work if trains are allowed to reverse at stations. This can be controlled in the game settings. Depending on your style of playing, it can be enabled or disabled, many players disable it, because train behavior gets easier to understand.
This is one half of a station design by krtaylor from tt-forums.net. The original layout used presignals, but it also works with path signals. Trains enter the station at the two platforms to the right (crossing the path signals as they are facing the other direction). After loading, trains can turn around and leave the station via the waypoint. One could experiment if the waypoint is really necessary, it is placed here for the sake of understanding the concept. The entry signal to the lower left is one-way to prevent trains going onto that track.
No turning around
If trains are not allowed to reverse in stations, one either has to build loops behind the station or build the platforms in such a way that trains enter a platform which is a dead end, forcing it to turn around.
In this example there is a loop behind the station allowing trains to turn around. The loop surely is not optimal because it might block trains coming from the right, but as long as only a few trains are to turn around, this should be ok.
Here, the loop is built a bit bigger and interferes less with the rest of the traffic. On the other hand, since it uses a bridge, the layout should only be used where the terrain is shaped in a fitting way, an extra slope just for turning might not be the best idea, especially not for heavy freight trains.
Here there is an extra platform in the middle of the station, which is a dead end, so it forces trains to turn around. To make sure that only trains go there that actually should do that, waypoints are used. Trains that should turn around use waypoint 1, the others use waypoint 2. This layout can also be extended easily and is also usable on heavily trafficked lines.