M.T.H. H9 2-8-0Steam Locomotive Operator's Manual page 5

Owners of 2-rail models who intend to run this locomotive on a 3-rail layout will
find a M.T.H. Proto-coupler assembly for this model packed separately in the
styrofoam box so that they may enjoy remote uncoupling action anywhere on a
layout. Simply remove the Kadee® Coupler Bracket. Attach the Proto-coupler
assembly to the rear truck with the supplied parts and connect the Proto-coupler
wire inside the tender.
Connecter
Coupler
Figure 6: 3-Rail Proto-Coupler and Connection
H9 2-8-0 Steam Locomotive
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