Re: Balloon loops on Australian tramways

[msbrader@interlog.com (Mark Brader)]

Would someone mind saying what makes a loop a *balloon* loop?  Here in
Toronto all the streetcars are single-ended, so all routes# end in a
loop of some kind.

Our simplest kind of loop consists of a sharp curve of say 60 degrees
in one direction and a similarly sharp 240-degree curve the other way,
in either order.  Most of the loop will be in a TTC-owned lot on one side
of the street.  (If the long curve is to the right, then the car runs
clockwise around the loop and, since we drive on the right, the track
must cross over itself.)  Of couse, there are many obvious variations
on the geometry due to the exact layout, and loops with extra tracks,
and so on.  Several loops are within subway stations and these require
sizable platforms for loading and unloading.

There are also places where a streetcar can loop while staying on streets,
just going "around the block".  Is a "balloon loop" simply meant to refer
to the above kind as opposed these on-street loops, or is there more to it?

#-There are one or two wyes [triangles] on the system, and one crossover,
  but they're never used by normal traffic or as normal turnback points.
-- 
Mark Brader, Toronto               "Argh!  Hoist by my own canard :-) !"
msbrader@interlog.com                                    -- Steve Summit

My text in this article is in the public domain.