Rapido Trains M-420 User manual

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MLW M420 LOCOMOTIVE PRODUCT GUIDELINES
Thank you for purchasing this Rapido Trains Inc. M420 locomotive. Our sound-
equipped M420 locomotive is powered by an ESU LokSound V5 decoder
and can be operated on DC or DCC layouts.
If you have any issues with your model, you can reach us by email: trains@
rapidotrains.com, by phone (1-855-LRC-6917 or 1-905-474-3314) or by snail
mail at the address below. (there is no address below)
Please do not send any models back to us without first speaking to us to
get a return authorization, and please be patient when you send something
back. When it comes to repairs, it’s something we don’t rush. We’d rather
get it right the one and only time we hope to ever see your model come
into our warranty repairs department. If you want to know the status of your
warranty return, you have two options: 1) contact us directly and ask, or 2)
complain about us on an online forum or Facebook. One of these methods
will result in a timely response and maybe a nice chat. The other will result
in a decaying radioactive isotope being hidden somewhere in your model
before it is returned to you.
If you are reading this and it’s the year 2050 or later, what took you so long
to read this manual? Of course, we’re assuming that you bought this model
when it was produced in 2021 (that was a wonderful year, wasn’t it?) and
that you just threw it on the track and didn’t even read this awesome little
book. I mean, it’s filled with so many great things and notes and information
... you know what, if you’re not going to read it, then I’m just not going to write
them anymore! There, I said it. Well, I guess I do have to continue writing this
manual, for the guys who are reading it in the 2020s.
CONTACT US!
Rapido Trains Inc.
500 Alden Road, Unit 21
Markham, Ontario
L3R 5H5 Canada
Tel. [phone]
Toll Free 1-855-LRC-6917
Fax. [phone]
Email. [e-mail]

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TABLE OF CONTENTS
Prototype History ...............................................................................................4
Break-In ............................................................................................................4
Minimum Radius Requirements .............................................................................5
Front Nose Door ................................................................................................5
Missing or Damaged Parts ..................................................................................5
Checking and Adjusting Your Locomotive ..............................................................6
Removing the Shell .............................................................................................6
Operation – DC (Silent).......................................................................................8
Installing a Silent DCC Decoder ........................................................................... 8
Operation – DC (Sound) .....................................................................................9
Operation – DCC (Sound)................................................................................. 10
• Locomotive Address ............................................................................. 11
• Turn On the Sound ............................................................................... 11
• Functions ............................................................................................ 12
• Functions: More Information .................................................................. 12
• Horns and Bells.................................................................................... 16
• Sound Volume Settings ......................................................................... 16
• Sound Volume Settings Chart ................................................................ 17
• Factory Reset ...................................................................................... 17
• More Information ................................................................................ 18
Limited Warranty ............................................................................................ 18
Acknowledgements ......................................................................................... 19
M420 DCC FUNCTIONS
F0 Headlight
F1 Bell
F2 Horn
F3 Curve Squeal
F4 Dynamic Brake (Though we’re not sure why you’d want this)
F5 Doppler Horn
F8 Startup/Mute/Shutdown
F9 Full Throttle
F10 Brake
F11 Class Lights
Sound-equipped Rapido models feature ESU Loksound V5
decoders. For more information, please visit www.esu.eu.

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PROTOTYPE HISTORY
The early 1970s were a time of massive change in Canadian locomotive design. CN’s
mechanical boss, Bob Radford, worked with MLW designers, locomotive crews and the
unions to devise a new cab design for freight road locomotives. This would become
known as a (Canadian) Comfort/Safety Cab. The first units to be equipped with this cab
was the M420 and it hit the rails in 1973, just a few weeks before the similarly-equipped
GP38-2(W).
The M420 was equipped with the ALCo 12V-251c3 prime mover producing 2000 H.P.
Most M420 units rode on MLW ZWT (Zero Weight- Transfer) trucks. The only exception
to this were the five units built for the Providence & Worcester, which rode on Type B
roadswitcher trucks as commonly found under most ALCo-designed 4-axle locomotives.
The P&W required a different bolster design and different truck spacing, making them
unique.
MLW constructed 103 M420s between May 1973 and February 1977 for four railways
including CN (80), BCR (16 including eight B units), Ferrocarriles del Estado (2),
Providence & Worcester (5).
CN would take delivery of the M420s in three groups: MR-20a class 2500-2529
(delivered 1973), MR-20b class 2530- 2559 (delivered 1974), and MR-20c class 2560-
2579 (delivered 1976).
All of the CN units were retired by 1998 and today many of these locomotives have
found second careers on short lines all over North America.
BREAK-IN
Don’t break into anyone’s layout room to steal their M420 locomotives. Or any units for
that matter! We’ll send some of our front-office staff after you if you do. Don’t believe us?
You should hear the threats we get from Janet when she doesn’t get her way! So just buy
more for yourself. LOTS MORE! But this isn’t about that kind of break-in.
Every locomotive needs a break-in period. Your M420 is no different and has been tested
at our factory for about a minute... maybe. Just long enough to know that everything is
assembled and working right. But that is not enough time to get the gears to mesh nicely
or to even out any jerky operation in a new motor. We suggest that, after reading this
manual, you put your M420 on a test loop and just let it run in each direction for an hour
or two. Fast and slow. Actually, don’t wait until you’re done reading the manual. Put it
on the track now! Start running it and let it run while you continue reading the manual.
And if it explodes because you didn’t read the manual, well…um…sorry. There already
should be enough grease in the gearbox so you don’t need to add any. Just let the thing
run and keep reading.

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MINIMUM RADIUS REQUIREMENTS
Being an average sized, 4-axle unit, the M420 will have no problems navigating 18”
radius curves and #4 crossovers. If you want to run them on anything smaller, may I
suggest switching your modeling to theme park operations?
I mean, really, when was the last time you saw an M420 go in circles? (No, that movie
where everything blows up doesn’t count!).
FRONT NOSE DOOR
You’ll note that the front door is removable and can be replaced with an optional
“opened” door. Neat, eh? Well it’s not just for looks, but we thought your crew should
have that fine “Canadian A/C” in the summer. After all, those cabs can get quite warm,
just ask Bobby when he was in OC&T’s cab for 8 plus hours on a 95-degree day. (Ed.:
You can tell Bobby wrote these instructions, because he’s a Yank and he talks funny. If it
were really 95° Celsius in that cab, Bobby would be on the menu for supper.)
You will find the “opened” door in the polybag. Carefully remove the “closed” door
(There are three stems that hold the door into place) from the nose. Remember! Place
the “closed” door somewhere you will be able to find it later! Winter gets cold and your
crew will need that door closed! (And we would rather not get a frantic email or phone
call saying how you lost the door or ants carried it away, off of the floor.) The “opened”
door will slide right into the three mounts.
WARNING! The door is not meant to be rotated on and off the nose! The pins holding
the door can easily break off and you wouldn’t want that! (Nor do we want to keep
reminding you that you broke the door off.) ANOTHER WARNING! DO NOT LEAVE
THE OPENED DOOR ON THE LOCOMOTIVE AND PUT IT BACK INTO THE ORIGINAL
CLAMSHELL. The door will break off! If you would like to leave the door in the opened
position and place the model back into the clamshell, you will need to clip away the
plastic around the door. Use a pair of nippers and gently (and carefully) (and more
gently) cut away the plastic on the clamshell. CN used to do this all the time on the
prototype when they would store it for the winter.
If you forgot to do this… Remove the now broken door, grab an old cereal box –
preferably a red one, like Honeycomb – and cut a new door out. Glue it into place. We
will gladly send a letter that says, “We told you so.” Rumour has it that Post matched
their Honeycomb cereal boxes to our CN red just for this occasion. We think they got it
wrong. Please write to them and complain.

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MISSING OR DAMAGED PARTS
With over 300 individual detail parts, the M420 is an amazing and complex model.
But that’s what we’re known for, isn’t it? To prevent inevitable frustration, we recommend
checking your locomotive as soon as possible to ensure that everything is where it
should be. We try to catch all potential issues at the factory, but with all 47 locomotives
in our production run it is possible that the odd problem may slip past our quality
control inspectors. Even after all these years, they still have karaoke nights and can get
tired during the day. Please cut them some slack. At least they know all the words to
“Wonderwall” by Oasis. (No, please do not send us an email and say, “You’re gonna
be the one that saves me” with a list of parts you need.)
A bigger issue is damage in transit. 99% of all models are perfect when they leave
our warehouse. But everyone knows that couriers and delivery persons don’t handle
packages like they’re filled with glass ornaments, so between our warehouse and your
front door there’s a chance that your model may or may not have been bumped, tumbled,
kicked or even slap-shotted. We have it on good authority that UPS drops off our models
with Les Habitants to use in hockey practice, then picks them up later to deliver to you.
No packaging is designed to survive a couple of hours on the ice at Brossard. When the
packages were delivered to Etobicoke, none of the boxes was damaged because the
Leafs kept fanning on the shot.
If bits come loose in transit, they are easily reattached with white glue, such as Weldbond.
We prefer Weldbond over CA because it works just as well for most layout scenarios
and is very easy to clean up. There is no risk of damaging the paint job – just wipe it up
with a bit of warm water on a paper towel.
If any parts are missing or broken, please call or email us and we’ll do the best we can
to take care of you, up to and including replacement parts if needed. And after all,
we’re your Wonderwall. OK, OK, I’ll stop. (Ed. Hey Zobby –most of our customers are
twenty to thirty years too old for your farkakte Oasis references. Go with some Simon
and Garfunkel. You can maybe go as late as Supertramp, but not a minute later.)
We aim for 100% customer satisfaction. Unless you are one of those people who calls
us because the bearing cap is sitting askew and you don’t want to gently push it back
into the truck. In which case, please go away.
CHECKING AND ADJUSTING YOUR LOCOMOTIVE
We try and make sure that every locomotive is perfectly up to spec before it leaves
the factory, but if the karaoke was particularly good the night before your model was
assembled there may be a couple of bugs. Doing a quick pre-service check will solve
most operational glitches.

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• Check to see that all wheelsets are correctly in gauge using an NMRA RP-2
Standards Gauge. Should any of the wheelsets be out of gauge, remove the
affected wheelset from the truck by prying off the bottom lid of the gearbox with
a small flat screwdriver and then spreading the side frames slightly. The wheelset
can be re-gauged by grabbing each wheel and twisting. Reverse the steps to
replace the wheelset and ensure the gearbox cover is snapped into place before
placing on the track. Don’t throw your model at the fridge in frustration.
• Check that all underbody piping and appliances are firmly installed and clear of
the track. A small drop of CA-type super glue will sufficiently hold any loose parts
securely. Under the body who cares if you spill a bit?
• Make sure that the trucks swivel freely and without binding. If they catch on
anything, check to ensure that the sand lines do not interfere with any of the
underframe components. If you really don’t like underbody detail, return this
model and go buy a brass M420 instead. We’re told they are very nice.
REMOVING THE SHELL
Removing the shell of the M420 can be a bit tricky, but we’re here to help guide you
through it. First, carefully remove the front nose handrails and the side handrails from the
cab. Once that is complete, you will need to carefully separate the battery boxes from
the cab. Take your time, as these parts can be fragile. The long hood has a few small
clips that lock the hood into place.
WARNING! The walkway does not need to be removed! Only the body shell and
cab do! Gently add pressure to the long hood near the walkway. Eventually you should
feel the body shell and cab begin to lift up. Voila, you’re done (Hopefully no parts
took off like a rocket onto the floor.) Twisting the engine strongly with both hands is not
recommended.
OPERATION – DC (SILENT)
If your M420 locomotive is not equipped with a sound decoder, it should function like
most other HO scale locomotives. The gear ratio is 14:1 so it should MU (multiple unit)
with your existing fleet. Put it on the track. Give it some juice. Watch it go. Wheeeee!
In DC, none of the class light features work. That’s right, none of them. If you want to
have the front and rear class lights work, then you might want to consider upgrading to
DCC. We know, we know, you are tired of people telling you to upgrade to DCC, telling
to upgrade to a colour television set, or reminding you that the last time a Canadian
team won the Cup was in ’93. (OK, I know. I’m fired.) (Ed. That is correct.)
But if you want to make all those cool locomotive features work, you will need a DCC

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system. Don’t wait until the Leafs win the Cup to upgrade to DCC, or you will never
upgrade to DCC.
INSTALLING A SILENT DCC DECODER
The M420 contains a motherboard which is connected to the track, motor, and lighting
outputs. It is located in the long hood. A blind plug is attached to the motherboard using
a 21-pin connector. To install a decoder, you will need to open your M420, remove the
blind plug and install a 21-pin decoder. You must use a 21-pin decoder rather than an
8-pin or 9-pin decoder. This is clearly written in Rapido’s laws and statutes, section 43,
subsection 122, paragraph 2175b.
We recommend the following 21-pin decoder:
• ESU #59619 - LokPilot V5 DCC with 21MTC
The necessary resistors are included on our motherboard, so you don’t have to futz
around with resistors. Just plug in the recommended decoder and you have DCC.
ESU has made an M420 function mapping which can be downloaded into their non-
sound decoder so that the function buttons and motor control are the same as our
factory-released sound versions. This is available for download on the M420 page in
the Support section of our web site. Well, it should be there. If it isn’t there, I blame the
Ottawa Senators. Go ask Melnyk for help. You will need an ESU LokProgrammer to
write the function mapping to the silent decoder. If you don’t have a LokProgrammer, you
can adjust CVs in the usual way.
You know, if you want silent DCC it’s a heck of a lot easier to just order the sound model
and turn off the sounds. If you’re known for mashing buttons on your controller errantly
and want to avoid sound altogether, open your M420 and either remove the speaker
or simply snip the wires to it. There, done! At any rate, after you’ve bought the silent
decoder and spent four hours fiddling to install it, fix the bits you broke off, and get
all the functions to work correctly, you’ll realize it would have been cheaper and less
frustrating to buy the sound-equipped model and just turn off the sounds. Your time and
sanity are worth something, after all!
For those of you reading this manual who have read all our previous manuals, we
apologize for reusing some of the text from previous manuals. The following word is
completely unique to this manual: cattywampus.
OPERATION – DC (SOUND)
Operation of a sound-equipped M420 on a DC layout is very similar to running a silent
DC model, except that the model will not move until it has reached sufficient voltage for

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the sounds to fire up (around 7 volts). You cannot control user-activated sound features like
the horn and bell if you are using DC. There are third party controllers that supposedly
activate these sounds on DC but after all these years we’ve still never tested them so we
have no idea how well they work or what they will do to your locomotive - for good or
for ill. If they cause your M420 to spontaneously combust, contact us for assistance, then
contact the third-party controller manufacturer and tell them they wrecked your brand
new Rapido M420. Crying is optional but highly recommended to get best results.
— NOTICE —
If you want to run your sound-equipped M420 on a DC layout, the Back-EMF
circuit can cause issues when you’re trying to bring your M420 to a stop. To turn
off Back-EMF, you will need to bring your M420 to a model railroad equipped
with DCC and set CV49 to 18. If you want to turn it back on, change CV49
to 19. If you have a large DC layout and you like to operate sound-equipped
locomotives, it might be worthwhile to invest in an entry-level DCC system just
so you can adjust the motor settings of your sound-equipped fleet off the layout.
OPERATION – DCC (SOUND)
This is the part where we discuss how neat the sound is. After being on an M420 for
two 10-hour days, I want to adopt one. (Ed. Bobby, you’re out of your mind.) OK, OK,
the 1:87th scale model is much easier to acquire. This beautiful locomotive has an Alco
251C, V12 prime mover that ESU has captured down to the signature rattle.
With that said, any locomotive can give off a slightly different sound, depending on
maintenance, workload or even what it had for breakfast. Maybe it had… Back Bacon!
Anyway, locomotives sound a lot different when they are actually working. If you have
decoders from other manufacturers in your locomotives you might want to check out
the available line of Rapido decoders on our web site. All of our decoder sounds were
recorded under load and we simply can’t stand decoders that don’t have this feature.
More detailed decoder instructions, including all sorts of weird CV settings we don’t
understand, can be found in the ESU LokSound V5 decoder manual. It is available for
download from the support section of our web site or directly from the ESU website.
LOCOMOTIVE ADDRESS
Your Rapido M420 comes from the factory with a decoder address of 3. We suggest if
you are using DCC control that you first test that the locomotive responds on address 3.
Once you have verified that the locomotive is responding you should assign it a unique
address (normally the road number of the unit) before going any further. This can be

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done either on your programming track (recommended) or on the main if your system
supports programming on the main. Be aware however that if you do program the
locomotive on the main and you have any other locomotives assigned to address 3 (the
normal default address for new locomotives) that ALL of them will also be changed to
your new address! This is great if you want to simulate a bunch of kids getting into the
engine shop, notching the controllers, and then running into the woods.
Note that some DCC systems get a little wonky when programming sound-equipped
locomotives on the programming track because of the high current draw. If weird stuff
happens, try programming on the main.
— WARNING —
Rapido products are designed to operate safely between 0V and 16V. Voltages in
excess of 16V - as well as irregular waveforms, voltage spikes or short circuits -
may cause severe and sometimes irreversible damage to the product. “Train set”
power packs are known to suffer from any one of these unexpected irregularities,
whereas higher-end systems have safeguards in place to prevent this. Rapido
always recommends using a power supply system that matches the quality of
the models you are running. If you’re reading this, you’ve obviously invested in
top-of-the-line, museum-quality motive power and equipment, so we hope you’ve
made the same investment with your model railroad power supply too.
While many power supply systems exist, some are known to have caused problems
with model train circuitry in the past. If you have any one of the following
systems, PLEASE DO NOT USE IT until you contact us for more information: MRC
RailPower 1300/1370-series, Bachman Spectrum Magnum, Atlas 313 Universal
Power Pack.
TURN ON THE SOUND
Press F8 and you will hear the M420 startup sequence followed by the sound of it idling.
You can adjust CVs to prevent the locomotive from moving until the startup sequence has
played out. Most of us at Rapido are really impatient so we turned this feature off. Refer
to a full ESU LokSound decoder manual for more information. You can download it from
the Support section of our web site.
If you press F8 when the locomotive is already moving, it will skip the startup and the
sound will just turn on. Press F8 again to turn the sound off.
Note that if you are listening to your M420 idling nicely and then you select another
engine, your locomotive still thinks F8 is pressed so it will keep idling along. However, if
someone else selects your locomotive’s number and F8 isn’t pressed on their controller,
the M420 will promptly shut down. They will need to press F8 again.

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FUNCTIONS
F1 Bell F12 Switching Mode
F2 Horn F13 Rear Light
F3 Curve Squeal F14 Radiator Fan
F4 Dynamic Brake (???) F15 Model Train Mode
F5 Doppler horn F16 Air Dryer on Shutdown
F7 Dimmer F17 Air Compressor
F8 Startup/Mute/Shutdown F18 Track Inspection Lights
F9 Full Throttle F19 Numberboard Lights
F10 Brake F20 Air Dryer
F11 Class Lights
FUNCTIONS: MORE INFORMATION
F1 Bell
Ding Ding Ding!
Probably one of the most difficult sounds to master is the bell, because it’s such a
noticeable feature and no matter what, chances are they all had their own unique tone
to them. So it really is up to the user to choose a bell to their liking. Thankfully, these units
were produced before the e-bells! No electronic ding, here!
F2 Horns
Who doesn’t love the sound of the Canadian K3L? A beautiful D# minor (D#, F# and A#),
which was produced by Holden, under license from Nathan Airchime in an early sand
cast and later die cast build. (OK Bobby, that’s entirely way too much info.) Thankfully,
this sound file provides a few versions of the K3L and a few others, in case you’re
adventurous. (You may also get a lecture from “Dr. Bobert Horn” about the incorrectness.
We’re sorry in advance.) To get a short “toot” just tap F2 or your “HORN” button. If you
hear a long tail-off you are tapping for too long. If, no matter what you do, you just can’t
get the darn thing to make a short “toot,” switch to NCE.
F3 Curve Squeal
Let’s face it, the curve squeal has been the greatest success we’ve created in recent years.
It’s absolutely wonderful. It sounds wonderful and can be easily applied to any train.
Since most yards and terminals featured rather tight-radius curves, it was never possible
for anything to SILENTLY go around them. Press F3 to wake up the neighborhood, and
subsequently press F3 again to turn off the noise and avoid a complaint. Now all we
need to do is get Jordan a haircut and we’ll consider it our next greatest success.
F4 Dynamic Brake
Press F4 to get dynamic brake sounds. Now listen, we know how modellers think, and
while we have included the sound, CN units DIDN’T HAVE DYNAMIC BRAKES! We

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just want to get that point across. If you have a CN engine and you press F4, you have
Green Cooties.
F5 Doppler Horn
Press F5 to hear a nice and slow Doppler K3L. Why not a fast Doppler horn? Well, when
was the last time you remember an M420 running like a rocket?
F7 Dimmer
See that oncoming train? Make sure you dim your headlights or ditchlights so you don’t
blind the crew! Hitting this function a second time will restore the lights back to bright.
F8 Startup/Mute/Shutdown
F8 toggles the primary locomotive sounds on and off. If you’re not moving, you’ll get a
nice startup sequence of the 251C prime mover. If your locomotive is already moving,
it’ll just go straight to the appropriate throttle step.
If you have a DCC system that only allows eight functions, you can remap the functions
following the guidelines in the ESU LokSound manual, which can be downloaded from
the support section of our web site. Or you can upgrade to a newer DCC system, which
may be less stressful.
F9 Full Throttle
No, it’s not that energy drink! This is ESU’s “Full Throttle” feature, that allows you to play
the prime mover of your M420 like a musical instrument. When you press F9, you turn
on “drive hold.” This keeps the speed of the engine constant at whatever speed step your
throttle happens to be on. Then as you increase the throttle, you hear the prime mover
revving up. This sounds awesome, whether you’re trying to make the grade with a slow
freight or revving the prime mover in the middle of the street after an ice storm. (Yes, this
really happened to an M420.)
“Full Throttle” is even neater when you throttle down, as it allows you to simulate
“coasting” which is such an important part of running a real train. When you press
F9 again you turn off “Full Throttle” and the engine will accelerate or decelerate to
whatever speed step your throttle happens to be on. For realism it’s a good idea to take
note of what speed step your throttle was on when you turned on “Full Throttle” and be
back at that speed step when you turn “Full Throttle” off. Otherwise your M420 may fly
like a twin-prop plane.
F10 Brake
F10 works just like the brakes on a real engine. Press F10 and you put on the brakes. Turn
off F10 and the brakes come off, so you start moving again.
F11 Class Lights
When you press F11, your white class lights will turn on. Hitting F11 a second time will

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cycle the lights to Green, a third hit will turn the lights red and finally, hit F11 again to
cycle the lights off. White Class lights were used to signify a train was running as an
extra in territory where train orders and schedules still applied. Green Class lights were
to signify that there was an additional (usually just a second) section of the same train
number, also in train order territory. The Red Markers are just neat! More on the use (and
different colors) of classification lights can be found in the Google. Truthfully, you have
absolutely no need for green or red class lights on an M420. We just put them there
because we think class lights are cool
F12 “Switching Mode”
If you press F12, the headlight and rear light will both be on dim. This is appropriate for
switching operations or for running light on the mainline. Press F12 again to turn off the
switching mode lighting.
F13 “Rear Light On/Off”
Pressing F13 will simply toggle the rear light ‘on’ and ‘off’.
F14 Radiator Fan
Press F14 to hear the radiator fans whizzzzzzz. DID YOU HEAR ME SAY HIT F14! I
CAN’T HEAR YOU!
F15 “Model Train Mode”
Pressing F15 changes the front and rear lights on your M420 to operate “the old-
fashioned way”. When your M420 is set to forward, your headlight will be on. When
it is set to backwards, your rear light will be on. Just like the good ole’ days of straight-
wired DC models, only better!
F16 Air Dryer on Shutdown
Want to hear those air dryers lay down a sick beat? Pressing F16 will activate the air
dryers on shutdown. This will sound neat and if you play your cards right, activate it
when it’s in a yard and the yardmaster has to work right next to it!
F17 Air Compressor
Pump that air up! By pressing F17, this will activate the air compressor, but by default, the
sound file will randomly play this feature.
F18 Track Inspection Lights
These lights shine down onto the roadbed. Why did we include them? Because they
look neat, of course. Oh, and your engineer will be happy at night when he’s making a
shove. By default, they are on. Pressing F18 will turn them off.
F19 Numberboard Lights
Toggle the numberboards on or off with a flick of a switch! (I mean “button,” unless you
have some type of neat DCC Controller or you managed to assemble a whole M420
stand in your basement.)

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F20 Air Dryer
To save you from the saliva clean-up should you try to mimic the sound of the spitter
valve, we’ve provided its sporadic sounds on F20. By default it’s always on, as the real
thing would always be going when the locomotive is running (and for a few minutes
after it’s shut down). But if you prefer to not hear it at all, just press F20 to silence the spit.
HORNS AND BELLS
Generally speaking, the M420s had K3Ls. (See above for a lecture by Dr. Bobert Horn.)
The default horn on your model is a Nathan K3L. If you wish to change the default horn,
you can do so by changing CV 163. For changing the default bell, change the value of
CV 164.
Horns Bells
•CV 163-0 Nathan K3L #1 (Default) • CV 164-0 - Bell #1 (Default)
• CV 163-1 Nathan K3L #2 • CV 164-1 - Bell #2
• CV 163-2 Nathan K5L
Changing the default horn automatically changes the Doppler recordings on F5 too.
SOUND VOLUME SETTINGS
The sound volumes on your decoder have been pre-set at the factory to levels that we
found comfortable on our test tracks.
Sound levels are very much a matter of personal taste (especially if you are going deaf
like we are), and what sounds great in one layout environment may sound too loud or
too soft in another. Fortunately, the sound levels can be easily adjusted to best suit your
own requirements and we recommend that you experiment with different settings if you
don’t care for the default levels.
To set the volume levels go into the program mode on your DCC system (refer to your
system’s manual for instructions on how to do this as each system is slightly different);
enter the desired CV number; then enter the desired levels. Note that this can be done
either on a programming track or on the main (ops mode) if your DCC system supports
programming on the main.
We strongly recommend that you keep notes on which settings you have changed, and
which values were used. If you ever need to do a reset on the decoder (see “Factory
Reset” below) then having good notes will allow you to easily re-enter any changes that
you wish to keep.

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M420 SOUND VOLUME SETTINGS
KEY FUNCTION SOUND SLOT CV DEFAULT YOUR VALUE
Master Volume 63 75
F1 Bell 4 283 70
F2 Horn 3 275 170
F3 Curve Squeal 23 435 30
F4 Dynamic Brake 6 299 99
F5 Doppler Horn 30 491 255
F8 Prime Mover 1 259 150
F10 Independent Brake 11 339 30
F14 Radiator Fan 8 315 50
F15 Isolation Switch 21 419 30
F17 Compressor 7 307 60
F20 Air Dryer 17 387 60
FACTORY RESET
On your M420, you can perform a factory reset by entering a value of “8” into CV 8.
Note that this will cause all your new volume and motor settings to be lost, so you will
need to reprogram any settings that you want to keep. What do you mean, you didn’t
take any notes? WE JUST TOLD YOU TAKE NOTES. You’re out of the band. Again!
You can NOT lose all the pre-recorded sounds on your M420 decoder by doing a
factory reset. However, after performing a factory reset your M420 may begin to sing
“The Hockey Song,” by Stompin’ Tom Connors. If that happens, you have probably lost
your mind. But don’t worry. If it’s a Saturday night, just sit back, grab some brewski, and
enjoy the game. Yes, I might be from the States, but I played hockey growing up, so I’m,
like, an honourary Hosehead, eh?
MORE INFORMATION
While addressing the features that most modelers will need for normal operation, these
instructions have covered just a small number of the many customizable features of your
ESU LokSound decoder. For advanced users who want to explore the capabilities of the
decoder more fully we suggest downloading the ESU LokSound V5 decoder manual.
This is available in the Support section of our web site.

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LIMITED LIFETIME WARRANTY
We will do our best to solve any problems or issues that you may have with your M420
locomotive. If your locomotive has any defects that originate from the factory, we will
repair your locomotive using new components or replace it outright should a repair not
be possible. However, we can only replace your locomotive while we have additional
ones in stock. We normally keep spares for up to six months after a model is released.
If you are like most of us and – after purchasing this locomotive – you dismissed it to one
of many cardboard boxes in your storage unit or backyard shed for the better part of
30 years (or how long it will likely be until the Maple Leafs win the cup again — that
should be 75 years — here come the letters. Remember, address them to me, Bobby, at
CBC Headquarters, Toronto) then you are on your own if there are any issues. The entire
Rapido crew will have hopefully won the lottery, and each bought their own private rail
cars, since Jason set the bar so high himself with our sleeping car, Edmundston.
There are several things that this warranty cannot cover. If your M420 arrives with a
couple of loose grab irons or underbody bits, there is a very good chance that you can
do a repair in less time and effort than it would take to contact us. Don’t be afraid to do
some model railroading! White glue, such as Weldbond, works wonders for securing
all sorts of parts and will not mar or damage your paint. However, if parts are missing
that is another story – call us or send us an email and we’ll send you some replacements.
Of course, damage caused by running your locomotive at full speed off the cliff known
as the edge of your 4x8 sheet of plywood, modifying your locomotive to work off
diesel fuel, using your locomotive to re-enact the explosive derailment scene from your
favourite railway movie (Yes, that one with the BC units carrying the nuclear load),
using your locomotive as an actual auxiliary power supply for a town in Quebec after
an ice storm (Happy thoughts, think happy thoughts), or any other damage caused by
you that we haven’t been able to cover here is not covered by the warranty. However, if
catastrophe does strike and your locomotive gets damaged, please give us a shout and
we’ll do our best to help you out.
Keep in mind the following: the most common reasons for Rapido locomotives not
working are dirty wheels or carpet fuzz/cat hair in the wheels and gears. Please visit
our YouTube channel and watch my helpful video about how to fix both these issues and
get yourself up and running again quickly. (Hey, did I just get un-fired?) (Ed.: NO.)

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ACKNOWLEDGEMENTS
The M420 project is a labour of love, a locomotive that for years was only available
in brass or resin. But not only have we pushed the bar to new heights, we also wanted
to show off our latest design concepts and features, like the neat nose doors or the
incredible detailing of the underframe. Much like the B36-7, it’s a locomotive that has
been passed over for far too long. Enter Rapido and the design team. Many trips to the
real thing, long days and late nights. Dreams do come true, eh? But, we wouldn’t be able
to accomplish all of this without some help from the experts.
Without the help of the following, none of this could have been possible:
Andrew Castle, Patrick Gagnon, Ken Goslett, Matt Herman, Cody Lee, Dave Minshall,
Rob Dingman and the Oil Creek & Titusville Railroad (We probably have worn our
welcome out, so we cannot thank them enough!) and the Ontario Southland Railway.
But wait, I think we’re missing someone. A very important figure…
You’ll note part of this manual is in French. Despite my grandmother growing up in
Montréal, I cannot speak French. However, we have the best translator in North America,
Richard Longpre. Did I mention it only took him .03 seconds for him to translate and
email this back to us? Even after we sent it to him last-second, told him it was due the
day before we sent it, he still puts up with us! Merci, M. l’Expert!

CN MR-20c class M420s 2567 and 2569, plus a GP40-2LW, passing through Berlin, New Hampshire in May, 1979. La 2567 et la 2569, deux M420 de la classe MR-20c du CN, traversent Berlin au New Hampshire accompagnées d’une GP-40-2LW.
R. Hood photo. Kaluza-Mueller collection
Photo R. Hood – Collection Kaluza-Mueller