R
K
AIL
ING
B y M T H E lectr ic T r ains
®
RAILKING SD-90 MAC
DIESEL ENGINE
OPERATING INSTRUCTIONS
Thank you for purchasing the RailKing® production of EMD’s SD-90
MAC diesel engine. The engine’s durable ABS body and die-cast trucks
are traditionally sized for operation on any O-31 Gauge track. The engine
should operate for years with any compatible AC transformer (see the chart
on page 35 for a list of compatible transformers) and is completely
compatible with most 3-rail locomotives, rolling stock and accessories.
The locomotive is equipped with either an electronic horn or the
ProtoSound® Digital Sound and train control system which contains several
deluxe features that are simple and fun to operate. Each feature is described
among the following pages which should be read before the engine is
operated. For those of you who can’t wait to get started, the Quick Start
Basic Operating Instructions found on Pages 3 and 4 should be read so that
you understand the basics of the operating system. Please note that some
features are only found in the ProtoSound® models and are marked as such.
Features not marked as ProtoSound® features are available in all models.
