Small Scale Railway Co. Product Information


Small Scale Railway Co. presents 2 families of low cost "on board"
sound units. These sound units are locomotive or rolling stock mounted
systems that operate from either track and/or battery power. They can even fit N Scale.

The 1st family of sound units is the "Mini-Prototype" Sound Unit product
line. These units feature automatically controlled sounds which have been processed
from recordings from actual engines. The 2nd family, the "Micro Sound"
product line, feature computer synthesized sounds, a more compact size intended
for hassle free N scale operation.


Mini-Prototype Sound Unit Description

The Mini-Prototype Sound Unit uses an optical sensor, mounted through the
floor of the loco or rolling stock, to monitor black and/or white stripes painted
on one of the truck axles. While in motion, the sound unit's microprocessor
can synchronize the chuffing sound to the change in light reflected off of the
striped axle. The microprocessor also uses this information to measure speed
and deceleration, and activate the various sounds that are programmed into each
sound unit.

Example:

At the first detection of movement, the microprocessor may select a combination
of sounds consisting of bell ringing, safe to proceed whistle or horn, chuffs,
and/or drain cock purges. Once the engine accelerates to a fast enough speed,
it will usually choose to give a prototype whistle pattern. While in motion
the steam engine type sound units will give real chuffs sounds. By default,
a prototype whistle or horn pattern will be given every 60 to 90 seconds. If
the user desires, an optional reed switch (or hall sensor) can toggle an input
that can activate the whistle or horn pattern when a magnet is passed along
the track to over-ride the pre-programmed intervals. This feature will allow
prototype whistle or horn patterns to be given at road crossings, passing trains,
switch towers, etc. on your layout. If the Mini-Prototype Sound Unit equipped
train slows at a reasonable rate, the microprocessor will activate the sounds
of squealing brakes. Passenger type steam engines will begin ringing the bell
upon detected deceleration. While not in motion, the sounds of air and/or steam
purges will be given with a randomly operating prototype air pump and running
steam generator sound.


optical sensor mounted over a truck axle on an HO box car



Similar to the steam engine, but the diesel burbles at idle until movement
is detected. After giving possible horn blasts and bell rings, the engine revs
up to it's optimum operating point for the generator. When moving, the higher
RPM sound of the diesel under load will be given. When the sound equipped freight
car slows down, again brake squeals might be given. After coming to a low enough
speed or stop, the engine will briefly "over rev" from the removed
load, and coast down to a near stalling, fuel starved "undershoot".
The diesel engine's controls will gently rev. the engine back to a stable idle.
Periodic air relief purges will be given every few seconds.

Most sound units contain 3 to 6 different prototype whistle or horn patterns,
that last anywhere from 1 Second to 20 Seconds in duration. Except for the diesel,
all sound units can generate 4 or more different types of "chuffs",
and many are capable of providing brake squeals. Each sound unit is different
and contains the sounds from the actual prototype. No "fake" sounds
have been generated by a synthesizer, all sounds are from real engines.

The sound circuit unit measures 3.7" x 0.6" and can fit into 3.7"
or longer tender, rolling stock and dummy engine shells. For larger scales,
size is less critical. The sound units can be purchased with 1 of the following
speakers sizes: 0.88", 1.1", 1.6", 2.0" and 2.5". A
"Basic" unit comes with a standard 9V Battery clip for $80. N Scale
users can either use this clip or remove the clip and use N, AA or AAA battery
clips available from most electronic supply stores. Three AA batteries can supply
enough power to allow the circuit to provide sound for almost 3 hours. A standard
9V battery can power the sound unit for 5 hours (some 9V batteries fit large
N scale box cars). The installation instructions contain information on how
to connect NiCad batteries so that they can be charged via track voltage.


Micro-Sound Unit Description

The are currently 2 Micro-Sound products. The "Micro-Chuff" (aka.
"Chuff Only") unit which produces only a computer generated chuff
sound. And the "Micro-Diesel" unit which produces a computer generated
diesel engine sound and a grade crossing horn when in motion. Like the "Mini-Prototype"
sound units, these units feature an optical sensor for speed and deceleration
measurement and the small circuit size. These units come with an AC to DC track
voltage converter, a NiCad battery that recharge from track voltage, and a 7/16"
speaker. When coupled with truck mounted electrical contacts, like those from
Kato, these units will generate sound at near 0 speed and the diesel will generate
the engine sound when not in motion. Since these sound units can operate from
track voltage and have their own NiCad batteries, you won't have to supply batteries
to keep these units powered. Either sound unit will fit easily into a 50 ft.
N scale box or stock car. The "Micro-Diesel" sound unit also features
a simple 3 chime horn, that will blast a grade crossing horn pattern (Long-Long-Short-Long),
every minute, or once every time it's trigger input to the microprocessor is
toggled. This will allow the horn pattern to be given at grade crossings, switch
towers, stations, etc. on the users layout (using a soldering iron, to connect
to circuit board contacts, the horn feature can be disabled).