Symbols to denote various posts and markers can be found in the same section as the sign symbols.

They are all inserted using the usual click and rotate principle that was used for symbolic road markings.

These items not only insert a simple 2D symbol, but when using 3D drivers eye view and 3D representation can be seen as part of the inserted item. It is also possible to turn on/off the 3D parts using the representations tab in the KeyProperties dialog.