Triangle display behind elements

Are the survey figures, etc. at elevation, or are they at Z = 0?

I'm not sure if there's any way to rearrange the draw order of items in a 3D file, if that's the problem. I seem to recall something, but I can't find it so I could be mistaken.

Sorry about that.  I'm talking triangles in my survey file.  I'd like the survey figures and any linework above the triangles.

The Triangles are a 3D element in a 3D file, your "Linework" is the corridor lines I assume.  So, the Triangles are a reference in a 2D file.  The update sequence for references can change what line vs graphics appear on top even if the elements are below the triangles.  This found in the Reference dialog > Properties > Update Sequence. In the update sequence list the first files in the list will appear under the last.  So, in the image below s22a183og_dtm.dgn (a 3D file) appears below the graphics in the last file in the list s22a183us2corridor.dgn. You can move them up and down in the list as needed.  Your corridor file should be a 2D file with a managed 3D model.