This report on spooky showhost holograms appearing on national TV might be a bit of old news..., but I guess still worth posting. The word "hologram" CNN uses in this Youtube, is misleading as such, for the effect appears on screen only and is not physically/visually/observably present in that studio.
The quality of the technique used, is supposed to be more advanced than it appears in the CNN interview. The 'blue-ish' halo around the projection is put there on purpose (it was recorded to a greenscreen background!). CNN wanted to make sure the audience knew that a real fake train was approaching.