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Destructive Switch Identification

We do not recommend this method as a first choice, however when the chain is broken off so short that advancing the positions is impossible, taking the switch apart can help identify the shuntings. Each switch operates in the same basic way, by rotating a small piece of conductive metal (a 'rotor shield') between four conductive metal contacts, which also serve as 'spring clips' to hold the wires in place. The positioning of the spring clips and the shape of the rotor shield determine what contacts are made in each position. The shape of the rotor shield can tell of its use.
ShuntMark and ID1st Pos - Off2nd Pos - Hi3rd Pos - Med4th Pos - LowWiringAppearance

or
SW200nn
Numerous Makers
'1' Over Chain
Numbers
in Order		 L - Black
1 - Brown
2 - Purple
3 - Gray
SW300nn
WELL TEC
or SANTA
'1' Over Chain
Numbers
in Order		 See Variants
for specific
wiring

L - Black
1 - Gray
2 - Yellow
3 - Pink

Double Stack
#913
Used with Transformer
Top layer is thicker (3/8")
than bottom layer (1/4")

Top Layer

.

.

Bottom Layer


Top
L - Brown
1 - to Bottom 2
2 - Purple
3 - Gray

Bottom
L - Pink
1 - empty
2 - to Top 1
3 - Black

Double Stack
Commander
Used with Choke or Taps
Both layers are 1/4" Thick

Top Layer

.

.

.

Bottom Layer


Convert to
Double Stack #913
with Transformer.