On Tue, 21 Aug 2007 11:24:21 -0500, with neither quill nor qualm,
Ignoramus2170 quickly quoth:

I bought a toy at a garage sale that is a "American Classic Express"
toy railroad with about 8" large cars etc. It is a bunch of rails,
cars etc, big in size etc. Very good appearance.

This is for my own kids.

The engine is broken. It makes a tooting sound, shakes a little but
does not move.

I took it apart, there is a geared transmission system with a bunch of
plastic gears stuck on metal shafts. One of the gears (5mm diameter)
that was supposed to be firmly stuck on its metal shaft (1 mm or so),
is now rotating around the shaft, therefore this system is not
transmitting rotation.

As a side note, I am really ****ed off by the disconnect between great
appearance of this toy railroad, and really cheap construction
thereof.

Anyway, I would like to know if there is a simple way to fix this
(other than making a replacement gear from metal, which is a PITA in
this size).

My friend, Terry, makes replacement teeth out of a a kit with powdered
nylon and some sort of resin. The output is quite strong. I don't
recall what brand he uses, but you can try something like this:
http://www.whitehorsepress.com/produ...oducts_id=4123

--
Books are the compasses and telescopes and sextants and charts which other
men have prepared to help us navigate the dangerous seas of human life.
--Jesse Lee Bennett