ProtoThrottle 201:
Configuration for Beginners

Overview

Welcome to ProtoThrottle 201. This course is designed to provide some simple recipes to get up and running with the ProtoThrottle quickly and easily. While the ProtoThrottle may at first seem daunting, if you take it step-by-step, as shown in the following material, you can be operating and enjoying the experience of the ProtoThrottle in very little time.

We start here assuming that you have a ProtoThrottle, have it set up and talking to your DCC system via a receiver, understand basic navigation through the ProtoThrottle menus, and are ready to set up your first locomotive to work with the ProtoThrottle. If that's not the case, or you would like a refresher course, then ProtoThrottle 101 is where you should begin.

So, let's get started.

Background

The ProtoThrottle is a model railroad throttle designed to mimic a standard EMD control stand. For operation of the locomotive, it includes a throttle with eight notches, a reverser handle with forward, centered, and reverse positions, and a brake handle. A spring-loaded horn handle, a push-on/push-off bell button, and two light knobs, one for the front lights and the other for the rear lights, round out the main controls. In addition, a screen and several buttons are available to navigate the various configuration menus and toggle functions on or off during operation.

One key point to remember about the ProtoThrottle... there is No Magic. The ProtoThrottle sends standard DCC speed, direction, and function commands to your decoder, via the command station. Sometimes there may be a little sleight-of-hand behind the scenes to fool your brain, but fundamentally, under the hood, the ProtoThrottle is doing nothing different than your standard DCC throttle.

It is just a throttle with a different (we like to think better!) face on it.

Tips for Success

Before delving into the recipes themselves, we would like to remind you of some important tips for success. These are all hard learned lessons, but if you remember and follow these guidelines, your experience will be that much better. Ignore them at your own peril.

• Be methodical. Take things step-by-step. It may seem slow at first, cumbersome, or too simple: "I just want to operate!". But don't do everything at once. Especially avoid jumpig to the more advanced features right away. Take your time, get your feet wet, go step-by-step and follow the instructions outlined below. After completing your first setup, it will go faster and you can then take some short cuts. But please, avoid doing that the first time.

• Keep it simple. Standardize. Work toward a common way of setting up your locomotives. This might start from a blank slate, or it might start from settings you got from a friend. But try to set up your fleet in a common, standard way. It may also mean that all your Tsunami2 locomotives are configured one way and all your Loksound locomotives another way - that's perfectly fine. But within those groups, standardize. Write down your settings each step of the way, and apply those same settings to subsequent locomotives. Don't "reinvent the wheel" each time.

• Test, Test... and test some more! This cannot be stressed enough. After making a change, test that change. Don't go making a bunch of changes, then try things only to be left wondering why it doesn't work. Test each step of the way. That way, if something doesn't work as you expected, you know the culprit exactly: the last (and only) thing you changed. As you configure more locomotives, and develop your standardized list of settings (remember the bullet above?), you can then get away with making more changes at once, going faster, and testing less frequently. But try not to fall into that trap initially.

When setting up your locomotives, you may very well encounter a situation where things just don't work like you expected. Fortunately, the ProtoThrottle provides some convenient diagnostic tools on the throttle itself. A description of these tools are available here and you are advised to review that material before proceeding.

With those admonishments out of the way, let's get to what you've been waiting for!

The Three Step Recipe

Configuration of a locomotive and the ProtoThrottle can be broken down into three main steps. Why these three steps? Experience has shown that doing these three things gets you to "90%" of the experience of operating with the ProtoThrottle. Sure, that number is somewhat fuzzy and not really based on any quantitative data, but the point is, you'll get most of the experience and fun (i.e. the "90%") just by doing these three simple things. That's the heart of the recipe.

The three steps are:

• Enable momentum
• Configure braking
• Set up lighting

After doing those three things, you will be able to enjoy operating your locomotive with the ProtoThrottle. Many people stop there and are perfectly happy. In fact, after going through the setup for those, which is discussed below, we encourage you to stop and operate for a while. Take some mental notes about what you like, what you don't like, what you would like to change. What else would you like the locomotive to do? Spend some time enjoying the ProtoThrottle experience and most of all... have some fun!

What about that final "10%"? This is where you can personalize your experience with the ProtoThrottle. It will almost certainly take more time, require more detailed configuration, and even get into the minutia of your specific brand of decoder. Is that your cup of tea? Great! If not, no problem! In either case, with the "90%" completed above, you will still be able to enjoy operating. If you do decide to pursue that last "10%", it can be done at your leisure, as time and your comfort level permits.

Pop Quiz

Where do we start?

A. Setting up a flattened speed curve

B. Dialing in momentum settings

C. Getting the step lights to work

You might think from the discussion above that the answer would be B, dialing in the momentum settings. You're almost correct. The correct answer is D (yes, it's a trick question): can you communicate with the locomotive?

Remember that tip about test, test, and test some more? Well, here's the first application of that, even before you've made any changes to the locomotive. If the ProtoThrottle can't communicate with the locomotive, it will be futile to try and do anything else.

Fortunately this check is quick and easy. First, go to the SET LOCO menu on the ProtoThrottle. Dial in the address, digit-by-digit. Short DCC addresses will be preceded by an 's' on the screen whereas long addresses have four numeric digits.

Now, test it. Pull the horn handle. Assuming you have a factory configured locomotive, the horn is almost always configured for F2. Conveniently, the ProtoThrottle also defaults to sending the F2 function when the horn lever is pulled. So in 99.9% of the cases, you should hear a horn sound coming from your locomotive.

If you do hear the horn, then great! Please proceed on to the next section.

If not, then stop here. Figure out why you aren't getting a horn sound. Do you have the correct DCC address set in the ProtoThrottle? Is the locomotive on powered track and making contact? Does the ProtoThrottle have a connection to the receiver on the layout?

A good sanity check is to try activating F2 with your normal DCC throttle. If that works, then the problem is likely somewhere between the ProtoThrottle and the DCC system. But if that doesn't work, then you need to dig deeper into why your normal DCC system's throttle can't communicate with the locomotive. Maybe an electrical problem? Maybe the locomotive horn function is, in fact, not F2? Solve that problem first before proceeding.

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Momentum

Why do we want high momentum? First of all, it's prototypical. Real trains have LOTS of momentum. They are big. They take time to get going. They take even more time to stop. Trains have a lot of mass and momentum is the consequence of that mass.

Another reason we want high momentum with the ProtoThrottle is that it smooths out the speed transitions between notches. Fundamentally, yes, the ProtoThrottle is an 8-speed throttle. But with high momentum, it successfully fools your brain into believing you have infinitely variable control of the speed (remember that sleight-of-hand comment above?). As the locomotive slowly ramps up and down in speed, you can control the speed by "playing the notches" using the throttle lever, just as a prototype engineer would need to do over varying terrain and with other forces acting on the train.

In the model world, we simulate momentum with settings in the DCC decoder. The decoder has two momentum settings, one for acceleration (going faster) and the other for deceleration (going slower).

Acceleration Momentum

The acceleration momentum setting is used when the speed of the locomotive is told to increase. It is set by CV 3. Higher values in CV 3 mean it will take longer to get up to the requested speed and simulates more mass.

Deceleration Momentum

When decreasing speed, the deceleration momentum setting is used. It is set by CV 4. A higher value here means it will take longer to slow down and to stop. This can also be thought of as a coasting effect, allowing the locomotive to keep moving (coast) even though you have throttled down and are no longer "applying power" to the wheels.

Operation Without Momentum

Before we get to setting up the momentum, let's take a look at how a locomotive behaves with the typical default settings. First, we accelerate with CV 3 = 0. Notice how the locomotive goes from stopped to moving almost instantly.

Next, we stop the locomotive with a setting of CV 4 = 0. Similar to above, the locomotive comes to a stop almost instantly when the throttle handle is moved to idle.

Now, let's adjust the momentum to get more realistic behavior.

Stopping with High Momentum

Since we don't have the brake set up yet, we have to rely on the emergency stop (brake lever all the way to the right) to stop the locomotive. You can turn this off later, but are advised to keep the emergency stop enabled on the ProtoThrottle brake handle until the brake is set up and working well in the next section.

Momentum Recipe

Acceleration: Start in the middle with CV 3 = 128. Test it out. Adjust to suit your preferences or layout size. Smaller layouts will tend to use lower values whereas larger layouts can get away with higher values. Intense switching operations may want smaller values, but relaxed branch lines may do better with larger values.

Deceleration: Set it to the max with CV 4 = 255. This will provide maximum coasting. We may adjust this later when setting up braking, but start here and leave it for now. Since we don't have braking set up just yet, be sure to have the emergency stop handy when testing.

Test and adjust CV 3 until you're happy. You can always come back later and adjust again, but get something in the ballpark of what feels right for acceleration on your layout. Leave CV 4 alone.

Operation With Momentum

The videos below show operation with momentum. Notice how the locomotive starts gradually and takes some time to reach the target speed.

When throttling down, instead of stopping immediately the locmotive coasts for an extended time. This is exactly the behavior we want so that the brake (coming up in the next section) can be used to bring the train to a stop exactly where you want.

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Braking

Why do we want braking?

Braking is a complement to the high momentum we set in the previous section, in particular the high deceleration momentum. This counteracts the coasting effect from CV 4 being set to the maximum value. With braking, we now have a more prototypical operation of the throttle: make the locomotive go with the throttle lever; make the locomotive stop with the brake lever.

ProtoThrottle Brake

The brake lever on the ProtoThrottle has smooth motion across its range. By default, the brake function activates at approximately the center position and is a simple on/off function. There are variable braking effects available, but we're going to ignore those for now. If you don't have the basic on/off braking working, trying to get something more advanced configured is a fool's errand (remember that thing about taking it step-by-step?).

By default, the brake handle is shared with the emergency stop function. Moving the brake handle all the way to the right will activate the emergency stop. This can be changed later, but for now, keep it so you have a quick way to stop the locomotive should that be needed.

The first thing you need to do is set up the ProtoThrottle to send the correct brake function to the DCC decoder in the locomotive. This is done in the CONFIG FUNC -> BRAKE menu:

• Tsunami2 = F11
• Loksound 5 = F10

The exact configuration recipe for the decoder varies by decoder type. Here we will cover the Tsunami2 and Loksound 5. Other decoder types are similar.

Tsunami2 Brake

The Tsunami2 decoder uses two configuration variables to set the brake rates in the decoder:

• CV 117: Independent brake rate
• CV 118: Train brake rate

Which one is in use at any one time is determined by the state of a function (typically F12). To keep things simple for now, set both CV 117 and CV 118 to the same value. That way it doesn't matter which one the decoder is using, you'll still get the same effect. Later you can go back and customize these to different values for different braking effects. But keep it simple for now.

On the Tsunami2 decoder, the brake rates shown above work in conjunction with CV 4, the deceleration momentum. We'll get to that interaction in moment with the recipe, but this is an important point to remember and an important distinction from other types of decoders.

One final note: make sure CV 1.403 is set to zero. If not, the brake won't work as expected. Many Athearn locomotives come from the factory with CV 1.403 programmed to a non-zero value, so you need to make sure to set this to zero before continuing.

Tsunami2 Brake Recipe

1. Set CV 117 and CV 118 = 255 (max)

2. Check that CV 1.403 = 0

3. Test & Adjust as needed:

   • Need more braking? Decrease CV 4 (keeping CV 117 & 118 = 255)
   • Need less braking? Decrease CV 117 & 118 (keeping CV 4 = 255)

JMRI Decoder Pro

The values for CV 117 and CV 118 shown in the recipe above are the values to use if directly programming the CVs. If using JMRI Decoder Pro, the Independent Brake (CV 117) and Train Brake (CV 118) fields are split into a Brake Rate and a Brake Rate Sign:

Set the Brake Rate Sign to the "Subtract value..." setting. Then, the Brake Rate is a value from 0 to 127, corresponding to the 128 to 255 range shown above for CV 117 and CV 118.

Loksound 5 Brake

The Loksound 5 decoder has three brakes: Brake 1, Brake 2, and Brake 3. However, to keep things simple, we're only going to use Brake 1, set by configuration variable, CV 179. The value of CV 179 sets the strength of the brake effect when the brake function is activated.

Loksound 5 Brake Recipe

1. Set CV 179 = 128

2. Test & adjust as needed:

   • Need more braking? Increase CV 179
   • Need less braking? Decrease CV 179

Braking Demo

The following video shows a light braking effect. When the brake is applied, the locomotive stops faster than when just coasting but still takes some time to stop.

However, if you want a stronger braking effect, you can adjust the CVs as explained above. Here, we stop with a heavier braking effect programmed into the decoder.

The key takeaway here is that you can (and should) experiment to get the effect that feels right for you and your layout.

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Lighting Concepts

The ProtoThrottle has two light switches, one for the front and the other for the rear. Each switch has four positions:

• OFF
• DIM
• BRIGHT
• BRIGHT + DITCH LIGHTS

Most decoders, especially factory-installed, come with headlights that automatically change direction when the locomotive direction changes. Since the ProtoThrottle has independent knobs for front and rear headlights, this automatic behavior is not desired. To stop this, we need to remove the directionality associated with the headlight function outputs by making them active in both the forward and reverse directions.

Additionally, we want independent control of each lighting output. Therefore, the front headlight, rear headlight, and front/rear ditch lights (if equipped) should be assigned separate functions.

Each decoder type configures the lighting outputs in different ways, using different CVs and has different spare/available functions. Additionally, everyone's preferences for which functions to use differs. Therefore, it is difficult to give one specific recipe for lighting configuration. We will present one example below, but you are encouraged to adapt this to your specific situation and create your own standard for your fleet.

Lighting Recipe

1. Assign front / rear headlights to different functions in the decoder

   • Front = F0
   • Rear = F28 (or something unused)

2. Assign front / rear ditch lights to different functions in the decoder

   • Front = F27 (or something unused)
   • Rear = F26 (or something unused)

3. Identify the dimmer function in the decoder

   • Tsunami2 = F7
   • Loksound 5 = F12
   • Always confirm with the locomotive or decoder manuals

4. Using the CONFIG FUNC menu on the ProtoThrottle, set the function numbers based on the values you chose above:

Setting	Description	Fn #
F.HEAD	Front headlight function	F0
R.HEAD	Rear headlight function	F28
F.DIM #1	Front headlight function	F0
F.DIM #2	Dimmer	F7 or F12
R.DIM #1	Rear headlight function	F28
R.DIM #2	Dimmer	F7 or F12
F.DITCH	Front ditch light function	F27
R.DITCH	Rear ditch light function	F26

Any unused lighting function(s) should be set to F–– (i.e. none).

A note about choosing functions...

In the example above, we chose high-numbered functions for some of the lights. This highlights one of the benefits of the ProtoThrottle: it doesn't care what function number is chosen and handles all of that for you behind the scenes once configured. However, if you plan to also use your locomotive with a regular DCC throttle, then you may want to choose lower-numbered functions so it is more convenient to select them on the conventional throttle.

90% Done!

You're there! Now is the time to stop. Operate your locomotive for a while. Feel free to go back and adjust things. But most of all, have fun!

After spending some time operating the ProtoThrottle, now consider what advanced topics you might (or might not) want to tackle. These could include:

• Align engine RPM with throttle notches
• Graduated (variable) braking
• Flattened speed curves
• Advanced lighting features
• Brake test
• Consisting

Conclusion

Hopefully this tutorial has given you the tools to confidently approach setting up a locomotive for the ProtoThrottle. Many thanks to the STL RPM crew for allowing us to present this as a clinic in 2025, to Scott Thornton and James McNab for help in preparing and reviewing this material, and most importantly, all of our ProtoThrottle customers for your support!