There are frequent questions from
individuals building modules on how to wire turnouts on the main line. In this
discussion, it helps to recognize that protecting the integrity of the main
line is a priority. If a member’s branch line has a problem, it is only a local
issue. If the problem shorts out the main line, then train operations for
everyone are affected.
The basic NTRAK requirements that need to
be met for main line turnouts:
· All branch lines
must be able to be isolated from the main line. A branch line can be powered
from the main line, but there must be a way to isolate it electrically if there
is a problem.
· Electrical
separation must be maintained between the three main lines, so a pair of
turnouts used for a crossover need to have an insulated joiner in each of the
divergent rails.
· Power routing
through the points is not allowed on the main line, so an additional power
connection must be provided on the divergent side of the turnout. You may power
route on the branch line.
· If an
alternate power source is to be used on the branch line it must be connected in
a way that prevents connecting to the main line.
The internal electrical connections are
different in each model turnout. For example, the PECO Insulfrog, PECO
Electrofrog, and Atlas turnouts are wired differently internally and provide
different challenges. A PECO Insulfrog will be used as the example in the
following discussion:
o a short siding without a lot of
electrical junk.” At least one switch will be required to provide power to the
branch line from the main line to meet the criteria that the branch line can be
isolated. Besides, a switch is very useful, allowing a locomotive to be parked
and isolated on the siding while others are running on the main line. The
switch can be located under the layout if desired. Figure 1 illustrates this minimal arrangement.

Figure 1:
Simplest approach to wiring.
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