MTHTrains RAILKING C&O 4-6-4 HUDSON User manual

RAILKING C&O 4-6-4 HUDSON
OPERATING INSTRUCTIONS
Thank you for purchasing the die-cast RailKing C&O 4-6-4 Hudson steam
locomotive. The engine’s die-cast body and tender are traditionally sized
for operation on any O-31 or larger layout. The engine is compatible with
any standard AC transformer, (see page 33 for a complete list of compatible
transformers and wiring instructions) and is completely compatible with
most other 3-rail locomotives, rolling stock and accessories.
The locomotive and tender are equipped with either an electronic whistle
or the Proto-Sound® 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 Proto-Sound® equipped
engines and are marked as such. Features not marked as Proto-Sound®
features are available in both versions.

2
RailKing C&O 4-6-4 Hudson Operating Manual
Table Of Contents
QUICK START - BASIC OPERATION(All 3-Rail Models) 3
PROTOSMOKE™ UNIT OPERATION 4
PROTO-SOUND® OPERATINGINSTRUCTIONS 5
Proto-Sound® DCRU® Reverse Unit Operation (All 3-Rail Models) 5
Whistle Operation 6
Bell Operation 6
ProtoCoupler™ Operation 7
Enhanced Neutral Steam Sounds 8
Squeaking Brake Sounds 8
Tips On Using The Squeaking Brake Sounds 9
Passenger Station Sounds (PFA) 10
Activating and Triggering Passenger Sounds 13
Tips On Using PFA Features 15
Special Reverse Unit Options 16
Self-Charging Battery Backup System 17
Replacing The Proto-Sound® Battery 17
Manually Adjusting Proto-Sound® Volume 18
USING “RESET" TO PROGRAM PROTO-SOUND® 19
Setting The Engine Volume 20
Programming For Squeaking Brake Operation 20
Programming For Whistle In Neutral Operation 21
Programming For ProtoCoupler™ Operation 21
Adjusting Chuff Rate 22
Programming For PFA Operation 22
Activating Remote Lockout Control 23
ResettingAll Proto-Sound® Options To Factory Default 23
OIL & LUBRICATION INSTRUCTIONS 25
TRACTION TIRE REPLACEMENT INSTRUCTIONS 26
LIGHT BULB REMOVAL & REPLACEMENT 27
TROUBLE SHOOTING PROTOSOUND®PROBLEMS 28
Proto-Sound® RESET Feature Chart 32
Transformer Wiring Chart 33
O-31 OPERATION 34
SERVICE AND WARRANTY INFORMATION 36
HOW TO GET SERVICE 36
LIMITED ONE YEAR WARRANTY 36

3
RailKing C&O 4-6-4 Hudson Operating Manual
QUICK START - BASIC OPERATION
The RailKing C&O 4-6-4 Hudson contains state-of-the art electronics with
several built-in automatic features for incredibly realistic operation. Despite
these advanced features, the C&O 4-6-4 Hudson is easy to operate with any
compatible standard AC transformer (see the compatibility chart on page
33). All models are equipped with an operating smoke system that should
be primed with smoke fluid before operating . Adding 15 - 20 drops of
fluid through the smoke stack should be sufficient. If you choose to not
prime the units with fluid, turn the smoke unit switch located under the
trailing truck to the OFF position. (See Figure 3 on page 4) This will
prevent any damage from occurring to the smoke unit when running the
engine without a primed smoke unit. For
more information see the section on page 4
on Smoke Unit operation.
The C&O 4-6-4 Hudson model is
controlled by a Proto-Sound® DCRU®
electronic reverse unit. The reverse unit
operates in the same manner that all reverse
units function by using forward, neutral and
reverse states that are entered each time the
throttle is turned on and off or by using the
transformer direction switch (if so
equipped).
The reverse unit is designed to
ignore dirty track, dead spots on
switches or minor short circuits
without disrupting the engine
operation, even at slow, prototypical
speeds. Before the engine can be
operated however, the reverse unit plug that extends out of the tender must
be inserted into the receptacle at the back of the boiler cab as seen in Figure
1. Once the plug is inserted, the throttle on the transformer can be
advanced. You will see that only the engine’s lights come on and that on
Proto-Sound® equipped engines, two dings from the sound system will
chime followed by the steam compressor pump sounds. The engine does
not run. This is known as the RESET state and is explained in more detail
beginning on Page 5. The Proto-Sound® DCRU® will not power the motor
until the throttle is turned OFF and then ON again. At this point, the engine
will now function just like any other electronic or mechanical E-unit.
Figure 1: Plugging in the tender harness
RESET
Neutral
Reverse
Neutral
Forward
Figure 2: Proto-Sound® DCRU® Cycle Phases

4
RailKing C&O 4-6-4 Hudson Operating Manual
PROTOSMOKE™ UNIT OPERATION
The C&O 4-6-4 Hudson contains a self-powered smoke unit that outputs a steady stream of
smoke through the smoke stack on the roof of the engine. The ON/OFF switch located next to
the trailing truck must be in the ON position in order for the smoke unit to function. See Fig. 3
below.
The smoke unit is essentially a small heating
element and wick which soaks up and then “cooks" a
mineral oil-based fluid that omits a harmless smoke.
The smoke is then forced out of the stack via a small
electric fan which runs at a constant speed. However,
the smoke intensity can be varied by increasing the
transformer voltage setting. The higher the setting,
the more intense the smoke output.
For best results, we recommend that you add 15 -
20 drops of ProtoSmoke™, Seuthe, LGB or LVTS
fluid before you run the engine. If you don’t choose
to add the fluid, then the smoke unit switch should
be turned off. Failure to either add the fluid or turn the switch off could lead to damage to the
smoke unit heating element and or wicking. Add the fluid through the smoke stack hole. After
adding the fluid, gently blow into the stack to eliminate any air bubbles. Do not overfill the
unit as overfilling can cause the fluid to leak out and coat the interior engine components.
When the smoke output begins to diminish while running the engine, an additional 10-15
drops of smoke fluid should be added or the smoke unit switch should be turned off. When
storing the engine for long periods of time, you may want to add at least 15 drops of fluid to
keep the wick soaked with fluid and prevent it from drying out. After removing the engine
from storage, it is advisable to add another 25 drops of fluid, letting the wick soak up the fluid
for 15 minutes prior to operation.
MAINTENANCE
CAUTION: Operating the engine without smoke fluid
and with the smoke unit switch in the ON position can
damage your smoke unit wick, causing the wick to
become hard, blackened and unabsorbant around the
heating element. When this occurs, it may be difficult
for the wick to soak up the smoke fluid resulting in poor
or no smoke output. If that occurs, we recommend that
you inspect and/or replace the wick taking care to not
run the engine without fluid in the future. You can
inspect the wick to see if it needs replacement by
removing the smoke unit inspection cover from the body
as seen in Fig.4. After removing the chassis and
inspection cover screws lift the inspection plate away
and inspect the wick. If the wick is darkly discolored
and hard, it should be replaced.
smoke unit switch
Figure 3: Smoke Unit Switch
Smoke Unit
Circuit Board
Mounting Screws
Smoke Unit Frame
Mounting Screws
Figure 4: Inspecting The Smoke Unit

5
RailKing C&O 4-6-4 Hudson Operating Manual
PROTO-SOUND® INSTRUCTIONS
The MTH Proto-Sound® digital sound and train control system provides
the operator with unprecedented realistic operation on your model railroad.
In addition to actual C&O 4-6-4 Hudson engine, CD-equivalent 16-bit
digital sounds, you get the following features:
1. ∗Built-In Proto-Sound® DCRU® Reverse Unit * Authentic Steam Whistle Sound*
Authentic Steam Bell Sound* Squeaking Brake Sound* Passenger Station
Sounds* Operating Remote Controlled ProtoCoupler™* Self-Charging Battery
Back-Up System With Automatic Battery Shut-Off* Remotely Controlled
Reverse Unit Lock-Out* Remotely Adjustable Steam Engine Chuffing Volume*
Authentic Steam Engine Neutral Sounds*
Each feature is described among the following pages. Though the system
is easy to use, we encourage you to read the instructions thoroughly.
Proto-Sound® DCRU® REVERSE UNIT
As mentioned in the Basic Operating section, the engine is controlled by a
DCRU® reverse unit that contains the standard forward-neutral-reverse
states found on most reverse units. However, as described earlier, when
power is first applied to the track, the reverse unit begins in RESET or what
seems like a neutral state. Power must be interrupted again to get the
locomotive to enter the forward state. It is this first RESET state that gives
Proto-Sound® its unique, remote controlled functions. The system will
enter RESET whenever power to the track is off for three or more seconds.
NEUTRAL will be referred to as the state between Forward and Reverse.
Proto-Sound® is equipped with a microprocessor, that, depending on the
amount of memory it is allotted, allows the user to utilize several remotely
activated functions. In the simplest terms, ProtoSounds® has its own
“Computer" controlling these functions. In order to access many of these
remotely controlled functions, the user must be in the RESET state to do so.
RESET is entered anytime power to the locomotive has been off for more
than 3 to 5 seconds. When the engine first enters RESET, the
microprocessor initiates a system check to determine if the system,
transformer and engine are operating correctly. This takes approximately
2.2 seconds during which you will hear the engine’s startup sounds begin.
In order for ProtoSounds® to properly initiate the system check, do not
advance the transformer throttle past 10 volts when you first enter RESET,
wait for the steam compressor sounds to begin and then slowly turn the

6
RailKing C&O 4-6-4 Hudson Operating Manual
transformer throttle to the off position and then back on again to enter the
forward phase. Interrupting the power too quickly may cause the system to
re-enter RESET (signaled by two dings of the bell). Should this happen,
wait longer before interrupting the power to enter the Forward phase.
Proto-Sound® comes with several programmable functions, including
remote Steam Chuffing Volume Adjustment, Separate Bell Button
Operation (pre-programmed at the factory), Whistle In Neutral Operation,
ProtoCoupler™ On/Off Control, Squeaking Brakes and Passenger Station
or Freight Yard Proto-Effects. Each of these features are described in more
detail later. You will notice that when in RESET, your engine will not
respond to the whistle button with a horn blast or continuous bell ringing.
In fact, when in RESET and the whistle button is depressed, only one single
bell chime will be heard each time the whistle button is pressed. If you
don’t want to configure or change your locomotive using any of these
programmable features, simply leave RESET and wait 2.2 seconds before
interrupting the power to put the engine in forward. After you leave
RESET, your engine will operate normally in all the direction states of
forward, neutral and reverse. Remember though, once power is turned off
for more than 3 seconds, the next time power is applied to the track, your
engine will be back in RESET.
WHISTLE OPERATION
Your C&O 4-6-4 Hudson Proto-Sound®-equipped engine is equipped with
a digital recording of a steam whistle. The whistle sound can be activated
anytime the engine is in forward or reverse by pressing the whistle button
on your transformer. The whistle will continue to blow as long as the
whistle button is depressed. The whistle will not function in RESET and
must be configured through a RESET option to allow the whistle to work
when the engine is in neutral. See page 21 for information on whistle
programming in the Using RESET To Program ProtoSounds®section of
this manual.
BELL OPERATION
Your C&O 4-6-4 Hudson Proto-Sound®-equipped engine is equipped with
a digital recording of an actual steam engine bell. The bell can be turned on
or off with any separate bell button, like the Lionel® Railsounds® No. 5906
Bell Button, by simply pushing the button. If you don’t have a separate
bell button, the bell can be controlled through your transformer’s whistle
button whenever the engine is in NEUTRAL. The bell will never ring

7
RailKing C&O 4-6-4 Hudson Operating Manual
continuously in RESET (Remember NEUTRAL is the state between
Forward and Reverse). Once the bell is turned on, it will continue to ring
when the engine is cycled into forward or reverse until you press the bell
button or re-enter NEUTRAL and turn the bell off with the whistle button.
In fact, because of Proto-Sound® state-of-the-art design, the
microprocessor remembers its last command. Therefore, unless you turn
the bell off before you quit running your train, the next time you run the
engine, the bell will come on. No matter whether you come back an hour
later or a year later, the bell will begin chiming once the engine enters one
of the three directional states.
To turn the bell on using the transformer’s whistle button, turn on power to
the track and cycle the engine into NEUTRAL. Turn the throttle to 8 volts
or less (any higher voltage will arm the ProtoCoupler™) and press the
whistle button. The bell should begin chiming. To turn the bell off, press
the whistle button again. If you want to keep the bell on while running the
engine, simply interrupt the power with the transformer throttle or the
transformer directional switch and enter forward or reverse.
PROTO-COUPLER™ OPERATION
Your C&O 4-6-4 Hudson Proto-Sound®-equipped locomotive tender is
equipped with a coil-wound ProtoCoupler™ for remote uncoupling action.
Because the ProtoCoupler™ is controlled through Proto-Sound®’s
microprocessor, it doesn’t require an uncoupling track section or
modification to your layout to function. The three simple steps below are
required to operate the coupler.
1. Put your engine in NEUTRAL and turn the throttle all the way up.
2. Press the transformer whistle button to “Arm" the coupler. (You
will hear a “Clank").
3. After arming the coupler, press the whistle button again to open
the coupler.
When the knuckle fires open you will hear the buzzing of the coil
energizing and the sound of the
air lines coming apart. It can
best be described as a
CHA-CHUSHHH sound. The
coupler doesn’t have to be fired H H
Put Engine In Neutral
At Full Power
Press & Release
The Horn/Whistle Button Press & Release
The Horn/Whistle Button
Listen For The
Ca-Clunk Sound
See The Coupler Open
And Listen For The
Cha-Chusshh Sound

8
RailKing C&O 4-6-4 Hudson Operating Manual
in NEUTRAL. Once the coupler is armed it can be fired in Forward,
Neutral or Reverse. However, you may find that the coupler doesn’t open
when firing the coupler at high speeds. Reduce the voltage setting on your
transformer if this occurs and
run your engine at a slower
speed before firing the coupler.
If the coupler continues to open
erratically, try lubricating the
knuckle with light oil as
indicated in Fig. 5.
ENHANCED
NEUTRAL STEAM
SOUNDS
The enhanced Neutral Sounds
can be automatically heard whenever the engine is in neutral. The sounds,
which include Steam Pop-Off, Steam Blow-Down, and Steam Injector
sounds occur every 2 to 30 seconds. Each of the three sequences will play
at random intervals to eliminate repetitive and boring sequences. While the
sounds are selected to play randomly by the microprocessor, there is no
guarantee that you won’t hear the same sound repeated twice or more times.
SQUEAKING BRAKE SOUNDS
Proto-Sound® equipped engines feature the ability to play the sound of
squeaking brakes whenever your engine slows in speed. There are two
settings for activating the squeaking brake sounds. The default setting
allows the brake sounds to play while the engine is in forward or reverse
and the transformer throttle is lowered from a high setting to a low setting
(14 volts to 8 volts or less). The other setting requires that a bell button be
used to “arm” the brake feature and is explained in more detail in the
“Activating Passenger Sounds” section found later in this manual. The
sound itself is a stored record on the ProtoSounds® software chip and will
always play the same brake sound for the same three second length each
time the voltage is reduced from
high to low. Some practice may
be required to synchronize the
playing of the brake sounds with
the movement of the engine. It
is not uncommon for the engine
oil knuckle
Figure 5: Lubricating The ProtoCouplers
Throttle Down From
High Voltage To Low Listen For The
Squeaking Brake Sounds

9
RailKing C&O 4-6-4 Hudson Operating Manual
to stop before the brake sound is completed. Operators will find that by
coordinating the movement of the throttle setting from 8 volts to off will
allow the engine to maintain its movement while the brake sounds play.
Note: The brake sounds will not be heard if the transformer throttle is
not set above 14 volts and/or not reduced below 8 volts.
TIPS ON USING THE SQUEAKING BRAKE FEATURE
Users will find the squeaking brake feature to be a very
realistic way to simulate the sound of an engine slowing down
for curves, crossings or coming to a stop at a station, side track
or switch yard. However, you may find that your engine
continues to play the brake sounds once your engine comes to a
stop, or that the sounds stop before the engine comes to a
complete halt. For example, if you simply run the engine and
turn the throttle off quickly, the brake sounds will likely
continue playing even though the engine has come to a
complete stop.
This effect can be eliminated by simply practicing with the
brake feature. In no time, you will quickly learn how to
“feather" the throttle to keep the engine moving while the brake
sounds play and then turning the throttle off just as the sounds
stop.

10
RailKing C&O 4-6-4 Hudson Operating Manual
Operating Proto-Sound® Passenger Station
Sound Effects
Passenger Station Announcements (PFA)
Proto-Sound® is equipped with operator controlled Passenger Station
Sounds, referred to as PFA. The PFA sequence is designed to simulate the
arrival, disembarking, embarking and departure of a passenger train in a
Passenger Station. This easy-to-use feature allows you to play digitally
recorded sounds of Passenger Station sounds while your engine is parked in
the Neutral State. No additional wires or modifications are needed to enjoy
these amazing sound effects. The sounds themselves are randomly
“shuffled” by the Proto-Sound® computer. This gives the system the ability
to play the various sounds in a different order each time PFA is enabled.
Activating Passenger Sounds -Quick Overview-
The following is a quick overview on how you can operate PFA.
The train on track moving Forward or Reverse direction.
B
Press and Hold Bell Button For 3+
Seconds, Listen For a Horn Blast or
Air Release, then Remove your Finger
from the Button.
BPress Bell Button Again Quickly to Stop Bell Chime.
Your train is now ready for you to play the PFA.

11
RailKing C&O 4-6-4 Hudson Operating Manual
d
Bell
Horn
Whistle
Direction
OR
To Play PFA, Stop Train Direction.
This Can Be Done by Pressing the
DIRECTION Button or Cycling the
TransformerHandle.
At This Time the Train Will Stop in
Neutral.
In a Few Seconds, An Arrival Message
Plays, Followed by a Background
Noise.
STOP
d
Bell
Horn
Whistle
Direction
OR Change/Press Direction- The Train Will
Remain In Neutral. It Will Continue to
Play More Background Noises.
d
Bell
Horn
Whistle
Direction
OR
Change/Press Direction- The Train Will Remain
In Neutral. You Will Hear a Double Air Release,
Departure Message Plays More Background
Noises.
d
Bell
Horn
Whistle
Direction
OR
GO
Change/Press Direction- The Train Will Remain In
Neutral. You Will Hear Closing Doors, Horn Blast,
a Few Bell Chimes and Train Departs in the
Direction the Train First Stopped.
For more detailed PFA instructions, read the following.

12
RailKing C&O 4-6-4 Hudson Operating Manual
Activating Passenger Sounds (PFA)-Detailed PFA Instructions
Arming The Passenger Sounds Feature
Before the Passenger Station sounds can be heard, the feature must be
activated. The feature can be activated in one of two ways.
ARMING THE PASSENGER SOUNDS FEATURE
Before the passenger station sounds can be heard, Proto-Sound® must
activate the feature so that the next time the engine enters the neutral
position, the sounds can play, The feature can be activated one of two ways.
Option 1:I f you are using the Z-4000® transformer, or any transformer
with a separate bell button controller, you can activate the feature by simply
pressing and holding the bell button for at least three seconds (it does not
matter if you are in forward, neutral or reverse). You will hear the bell turn
on and, after three seconds, you should hear a short whistle blast or air
release. Once the
whistle blast or air
release is heard, the bell
button can be released.
The bell will continue to
chime, so if you want to
turn off the bell ringing,
simply press and release
the bell button. If you were in neutral, interrupt the transformer throttle to
enter the next directional state (either forward or reverse). (Note: the PFA
will only play in the first Neutral after it is armed. You can not interrupt
the power twice to enter another direction and still have the PFA active.)
You can now trigger the sounds to begin playing when you next enter
Neutral.
Option 2: If you do not have a separate Z-4000® transformer (or separate
bell button available), you can activate the PFA using your transformer’s
whistle button control. To arm the PFA, turn on the transformer throttle and
cycle your engine into
Neutral (not RESET).
Once in neutral, set the
transformer throttle to 8
volts or less and press and
hold the whistle button for
Put Engine In Neutral,
Forward or Reverse
Press & Hold
The Railsounds® Bell Button
For 3 Seconds
Listen For The
Start Of The Bell Sound
Listen For The
Air Release Sound
After 3 Seconds
Put Engine In Neutral
At Low Power
Press & Hold
The Horn/Whistle Button
For 3 Seconds
Listen For The
Start Of The Bell Sound
Listen For The
Air Release Sound
After 3 Seconds
H

13
RailKing C&O 4-6-4 Hudson Operating Manual
at least three seconds. You will hear the bell turn on and, after three
seconds, you should hear a short whistle blast or air release. Once the
whistle blast or air release is heard, the whistle button can be released. The
bell will continue to chime, so if you want to turn off the bell ringing,
simply press and release the whistle button. Interrupt the transformer
throttle to enter the next directional state (either forward or reverse). (Note:
the PFA will only play in the first Neutral after it is armed. You can not
interrupt the power twice to enter another direction and still have the PFA
active.) You can now trigger the sounds to begin playing when you next
enter Neutral.
ACTIVATING AND TRIGGERING PASSENGER
STATION ANNOUNCEMENTS
Once the PFA feature has been activated, it will be played the next time the
engine enters neutral. At this point, Proto-Sound® will take over control of
your engine, disabling the bell and whistle button. In addition,
Proto-Sound® reconfigures the way the reverse unit functions during the
operation of the PFA feature. This forces the engine to leave your
Passenger Station in the same direction as it arrived. The following
operator controlled “Events” control the PFA’s actions and sounds. (Note:
The direction states shown assume the PFA is entered from forward. If
entering the Passenger Station in reverse, the direction states shown will
be reversed.)
Event 1: Interrupt the transformer throttle to cycle the engine from forward
into neutral. If the throttle was at 14 volts or higher, the squeaking brakes
sound will play. Once the engine is stopped, the throttle must be turned on
to keep it in the neutral state. Note: Failure to turn the throttle back on
within 3 seconds of leaving forward will disable PFA and shutdown
Proto-Sound®. The next time
power is turned on, the engine will
be in the RESET position. See page
19 for additional information on
RESET. If the bell was not turned
off after arming PFA, it is now
turned off automatically. After
entering neutral, Proto-Sound® will immediately play a whistle blast or an
air release sound, followed approximately 2 seconds later by an Arrival
Announcement. Following this arrival announcement, the sounds of doors
opening and the conductor saying “Watch your step” is heard. At this point,
various Passenger Station sounds can be heard, including passenger
Put Engine In Neutral
At Low Power Listen For Air Release Sound
And PA Arrival Message

14
RailKing C&O 4-6-4 Hudson Operating Manual
footsteps, muffled voices, baggage being moved about and whistling for a
taxi. Additionally, several conductor highlights will be heard in the
foreground.
Event 2: Interrupt the transformer throttle
again to cycle the engine from neutral into
reverse. In order to have the engine leave
the yard in the same direction it entered
Proto-Sound® disables the motors in this
reverse state to prevent the engine from
running backwards. PFA confirms reverse
is entered by playing the conductor saying
“Baggage to the right/left.” Once this
highlight is played, the Passenger Station
sounds heard in Event 1 will continue to play.
Event 3: Interrupt the transformer throttle
again to cycle the engine from reverse back
to neutral. PFA confirms that the engine is
now in neutral by sounding two quick air
releases. This is followed approximately
two seconds later by a Boarding
Announcement message and continued
Passenger Station sounds. Conductor
highlights, such as “Welcome aboard” and
“Tickets please” will play randomly.
Event 4: Interrupt the transformer throttle again to complete the PFA
feature and cycle the engine into forward. PFA confirms it has entered
forward by playing the conductor’s call “All Aboard!” and the sound of the
passenger car door closing. Within two seconds, the whistle will sound two
short blasts (three if entering reverse), and
the bell will begin to chime. After a few
chimes of the bell, the engine will begin
moving in forward with the bell continuing
to ring. A few seconds later, the bell will
turn off, and the engine will resume normal
operation. Note: When entering Event 4, it
is important to set the transformer throttle
at a high enough setting that the engine will
begin to move when the motors are activated. However, the throttle
should not be too high for the engine to maintain a safe operating speed.
Listen For 2
Air Release Sounds
Interrupt Throttle To
Enter The Next Phase
Listen For The
Conductor To Say ...
Interrupt Throttle To
Enter The Next Phase
Listen For Conductor
To Say ...
Interrupt Throttle To
Enter The Next Phase

15
RailKing C&O 4-6-4 Hudson Operating Manual
TIPS ON USING THE PFA FEATURES
PFA is a unique feature of Proto-Sound® that is completely controlled by the
operator. You decide how, when or if you want to utilize the feature. By
reviewing the following tips, you should find solutions or suggestions to the
various operating scenarios you might encounter when using PFA.
Tip#1: You can escape the PFA sequence by interrupting the transformer
throttle before the man’s whistle plays in Event 1 (neutral).
Tip#2: You can exit PFA at anytime by turning the transformer throttle Off
for 15 seconds.
Tip#3: You do not have to be in Forward to utilize PFA. For example, if you
activate the PFA feature while in Reverse, your train will leave the station/yard
in the same reverse direction that it arrived in.
Tip#4: You can use PFA even if you are double-heading with another engine
regardlessofwhether the second engine isequippedwith an PFA programmed
Proto-Sound® module. If the second engine isn’t equipped with PFA, the only
thing to remember is that you not to turn up the transformer throttle very high
when entering Reverse in Event 2. If the throttle is set too high, then the
second locomotive will begin vibrating on the track as its motors will be
turning in reverse. If your second engine is equipped with PFA, you may want
to disable the PFA when used in double-headed operations. To disable PFA,
see the section on programming RESET functions on page 19 of this manual.
Tip#5: You can leave any of the event stages at any time by simply
interrupting the transformer throttle. Any sound effects programmed to play in
that event will simply not occur. The only exceptions are Event 1 and Event 4.
In Event 1, interrupting the throttle has no effect on PFA until after the man’s
whistle has completed and the freight car doors have opened. In Event 4, you
cannot interrupt PFA until after the engine begins to move. Interrupting the
throttle before the engine begins to move has no effect on the locomotive’s
operation.

16
RailKing C&O 4-6-4 Hudson Operating Manual
Special Reverse Unit Options
Reverse Unit Lockout Operation
For operators who wish to lock their engine into a single direction,
Proto-Sound’s® unique design eliminates the need for a lock-out switch
on the locomotive. This will allow users to run the engine on layouts
equipped with block signals or stop stations that would normally cycle
the engine back into neutral.Note: The feature must be first turned on
by accessing RESET Feature 40 (See page 23).
Locking the Engine into Single Direction Operation
Cycle the transformer throttle so that your engine is operating in the
direction you wish to lock it in (forward, neutral or reverse). With the
throttle set to approximately 8 volts, press and hold the horn/whistle
button. While holding the horn/whistle button, turn the throttle OFF,
then release the horn/whistle button. After 2 seconds, you will hear a
short whistle blast. IMMEDIATELY turn the throttle back on. The
engine is now locked, and will continue in the previous direction
whenever power is applied to the track.
Unlocking the Engine
With the throttle set to approximately 8 volts, press and hold the
horn/whistle button. While holding the horn/whistle button, turn the
throttle OFF, then release the whistle button. After three seconds, a
single bell will be heard indicating that the engine is unlocked. When
power is again applied, the engine will enter RESET and perform as
normal.
NOTE: When locking the engine in the Forward or Reverse positions,
the horn/whistle button will blow the horn/whistle. But when locking
the engine into the NEUTRAL position, the horn/whistle button may
turn on or off sounds of the bell. Remember, the horn/whistle doesn’t
blow in NEUTRAL (unless you programmed it to do so using Reset
Feature 25 - see page 21 for details), only the bell rings.

17
RailKing C&O 4-6-4 Hudson Operating Manual
SELF-CHARGING BATTERY BACKUP
Proto-Sound® state-of-the-art design includes a self-charging battery
backup system for improved performance at any speed. The battery ensures
that power to the sound system will remain on during directional changes,
while setting RESET options or when traveling over spots of dirty track and
switches. The self-charging battery backup system is automatically turned
on or off whenever track power is turned on or off.
Proto-Sound® contains a warning alarm if the battery backup system fails
to automatically disengage when track power is turned off. Should the
backup system fail, you will hear a repeating horn or whistle blast
indicating that this has occurred. Should this happen, unplug the battery
from the Proto-Sound® module (to prevent the battery from being run
down) and contact MTH for instructions on returning the train for repair.
REPLACING THE PROTO-SOUND® BATTERY
The Proto-Sound® battery is a special NiCad 7-cell, 8.4v battery -NOT the
6-cell, 7.2v battery found in most convenience stores. The 6-cell NiCad is
NOT recommended for use with Proto-Sound® applications. The battery is
continually charged from the track when power is applied and should last
for up to five years. In addition, the NiCad battery is a dry battery and
should not leak or cause any damage to your locomotive during its lifetime.
If you notice that the sounds seem distorted or garbled at low voltages or
become silent when power from the transformer is shut off, the battery may
be going bad. Before replacing the battery, you should put the engine in
NEUTRAL and leave the transformer throttle set at about 12 volts for 15
minutes. This should temporarily recharge the battery. If the garbled or
distorted sounds are reduced, then your battery charge has worn down. You
can give your battery a full charge by leaving the engine ON in the
NEUTRAL position and the transformer throttle set at about 12 volts for 6
hours.
Note: When charging the battery in neutral, if your trains contains a
Smoke Unit, it should be turned OFF to prevent damage to the wick and
the heating elements
If you need to replace the battery, they are available from MTH
Proto-Sound® Electronics at 7020 Columbia Gateway Drive, Columbia,

18
RailKing C&O 4-6-4 Hudson Operating Manual
MD 21046-1532. A standard 9v alkaline battery can be substituted as a
temporary fix, but, since alkaline batteries can’t take a charge, it will
eventually wear down.
MANUALLY ADJUSTING PROTO-SOUND® VOLUME
Your Proto-Sound® system has two types of volume adjustment. A
manual turn knob on the bottom of the chassis (See Fig. 6 below) allows
you to control all the sounds in the system and a remote control “RESET"
option (Option # 6), allows you to control the volume level of the engine
sounds remotely from the transformer. Turning the volume adjustment
knob clockwise will increase the volume and counterclockwise will lower
the volume of all sounds; bell, whistle, engine sounds, enhanced neutral
sounds, etc. For information on operating the RESET volume adjustment
option, see the section entitled “Programming Proto-Sound® RESET
Options” on the following pages.
Proto-Sound® VolumeAdjustment Knob
Figure 6: Adjusting The ProtoSound® Volume

19
RailKing C&O 4-6-4 Hudson Operating Manual
USING “RESET" TO PROGRAM
PROTO-SOUND®
Proto-Sound® is equipped
with
several programmable
features which are
accessed in the RESET
state by moving the
transformer throttle up
and down between full
voltage and low voltage (8 volts) without shutting the transformer off
completely. Each time this is done you advance, one feature at a time,
through the available options. An air-release sound is heard each time the
throttle is advanced and returned. In addition, there are special sounds to
tell you what RESET position you are in.
For example, if you want to select Feature 2, put the engine in RESET, and
move the throttle up and down from full throttle to low two times. After the
second advance, you will hear two “clinks" indicating that the computer is
now in Feature 2. Advance the throttle again and you will hear three
“clinks" for Feature 3. Advance it two more times and you will hear a
“clank" indicating that you are now in Feature 5. Advance the throttle two
more times and you will hear a “clank" and two “clinks" indicating Feature
7. ((5 throttle advancements = 1 clank) + (2 throttle advancements = 2
clinks)). “Clank” + “Clink" + “Clink" = Feature 7. You can advance the
throttle as quickly as you like and the computer will still remember the
number of times the throttle is advanced by playing back the number of
“Clinks" and “Clanks" to confirm the feature you’ve selected.
In RESET Mode
Move The Throttle
Up & Down From
High Voltage To Low
2 Times
Advance The Throttle
Up & Down From
High Voltage To Low
4 More Times
Listen For The
2 Clink Sounds
Listen For 1 Clank
And 1 Clink Sounds

20
RailKing C&O 4-6-4 Hudson Operating Manual
Remotely Adjusting The Engine Volume - Reset Feature 6 – (1
Clank, 1 Clink)
Reset Feature 6 allows
you to change the
volume setting of the
chuff sounds without
affecting the volume of
other sounds, such as
whistle, bell, enhanced
neutral sounds, etc. To
use, cycle to Reset 6 and press the Horn/Whistle button. A single bell will
play, and the chuff will begin at the current volume. Each time the
Horn/Whistle button is pressed, a bell will sound and the volume setting
will cycle down to the next level. The levels available are 100%, 50%,
25%, and 0%. After 0%, pressing the horn/whistle button again will return
the chuff to 100%. When the desired level is reached, lock the changes by
interrupting the throttle and cycling the engine into forward.
Programming For Squeaking Brake Operation- Reset Feature 45
–(9 Clanks, 0 Clinks)
Reset Feature 45 allows you to determine if and how the Squeaking Brakes
recording will be activated. To use, cycle to Reset 45 and press the
Horn/Whistle button. The engine will play a series of bells. This indicates
the current setting. Each time the Horn/Whistle is pressed, Proto-Sound®
will cycle to the next
available setting and
provide the appropriate
bell indicator. The
settings for Reset 45 are 1
Bell = On Demand
(Enabled when PFA is
activated), 2 Bells =
Always On, 3 Bells = Off.
When the desired setting is reached, lock the changes by interrupting the
throttle and cycling the engine into forward.
In RESET Mode
Move The Throttle
Up & Down From
High Voltage To Low
6 Times
Listen For 1 Clank
And 1 Clink Sounds
Push The Horn/Whistle Button
Until You Reach The
Setting You Desire
Interrupt The Throttle
To “Lock-In”
The Volume Setting
H
In RESET Mode
Move The Throttle
Up & Down From
High Voltage To Low
45 Times
Listen For 9 Clank
And 0 Clink Sounds
Push The Horn/Whistle Button
Until You Hear The
Appropriate # Of Dings
Interrupt The Throttle
To “Lock-In”
The Brake Setting
H