Stephen G. Hatch
Resident Wizard Railway Engineering
on all subjects.
Subject: How to hook up and wire a three way stub switch.
First examine the problem:
Three switch frogs in the space of one turnout.
Actually, the center frog can be ignored as it will be powered
by one of the other frogs, and.....
The two outer rails (stock rails) can be hard wired to
the rest of the track, so let's call them +pos and -neg.
Allright, now we have the two frogs. Let's call them left
and right as in the diagram below. Now the problem.
1. Left (lf) frog must be -neg to run left (left stock is +pos)
2. Left (lf) frog must be +pos to run center.
3. Right(rf) frog must be -neg to run center.
4. Right(rf) frog must be +pos to run right. (right stock is -neg)
The three positions we need are:
Left Center Right
neg lf rf .... pos lf neg rf .... pos lf rf
pos negative pos neg positive neg
Electric -> + - - - + + - - + + + -
\ \| |/ / \ \| |/ / \ \| |/ /
\ \ | / \ | | / \ | / /
\ \|/ \| |/ \|/ /
moveable stub-> +\ \- +| |- +/ /-
Railway Engineering Turnouts are insulated this way.
A Two pole Three position switch will do nicely and is called a
rotary switch (available from radio shack) or 3 position slide switch
There is a wafer in the rotary switch that can be drilled with a
small hole and piano wire hooked to actually move the stub rails.
( stubs are wired just like the stock rails pos neg )
Or use a three (3) position slide switch with holes in the
bat to actuate the stub rails.....like this: