See also: the New York pneumatic mail system (although that didn't move people).
<a href="http://untappedcities.com/2013/03/15/nycs-pneumatic-tube-mail-network/" rel="nofollow">http://untappedcities.com/2013/03/15/nycs-pneumatic-tube-mai...</a><p>(not to be confused with Beach Pneumatic Transit, although that didn't move mail: <a href="http://www.columbia.edu/~brennan/beach/" rel="nofollow">http://www.columbia.edu/~brennan/beach/</a> )
> <i>That year, Royal Mail said the line cost five times as much as using roads and the network shut down.</i><p>I wonder if that calculated cost of using roads included the externalized costs of using roads – exhaust emissions, traffic congestions, road wear, etc.