Multiple realities(covers information from several alternate timelines)
A tram was typically a land vehicle designed for public transportation. They were common in San Francisco.
By the 23rd century, air trams, trams capable of atmospheric flight, were in common use, although the traditional street variety were also still in use. (Star Trek Into Darkness)
San Francisco had their own air tram stations. Starfleet personnel were transported to Starfleet Headquarters through this method of transportation. Rear Admiral James T. Kirk, for example, once rode aboard air tram 3. (Star Trek: The Motion Picture)