Søren's Model Railway Pages

About model railways in H0


Function mapping with Märklin decoders and the Central Station 2

Function mapping is a great way to add effects and features to your locomotive which were not originally factory-programmed. In this article I will show you how to give life to your shunting function by turning on the correct warning lights on the locomotive.

When German locomotives are shunting in the yard they turn on what is called the "double A", meaning that the front light on both ends of the locomotive is on. The front light, two lower- and one top lantern, forms the letter A, hence the double A when both ends are on.

If you have a Märklin decoder from the mLD, mSD family and a Central Station 2 you can easily mimic the double-A behaviour when pressing the shunting mode button. Using the Central Station 2, it only takes a few minutes to make the correct adjustments in the decoder.

In this example I will add the double-A feature to a class 185 from Trix. I have already fitted the locomotive with a 21-pin mLD (Märklin #60942). With the loco on the track, click the little wrenge button to get into the locomotive configuration screen.

A model train
Clicking the wrenge button will open the locomotive configuration screen.

From the locomotive configuration screen you are already able to do some adjustments on the functions, but to be able to do actual function mapping, you will need to go to the CV-list. Click the CV button to open the CV-list.

Note: The locomotive is registered as an mfx-locomotive for this example.

A model train
Function mapping can only be done from the CV-list.

The CV list will take a few seconds to load. You will see a progress bar on the screen while the Central Station 2 loads the values.

A model train
Wait for a few seconds for the values to load...

With the values loaded, you are now able to configure function mapping for each function. In the column to the right, you will see the available functions. Since we are going to configure the shunting function, we click the shunting icon (the turtle). This will load the function map for the chosen function.  

A model train
The function map for the shunting function.

In the actions column you can add functions to be activated by the shunting mode key. I have already added the functions I need to turn on the double-A and the shunting mode ("Rangiergang" in German).

You add additional functions by hitting the "+"-key and choose the function from the drop-down list. All functions in the action-list will go on when the function key is hit (in this case, when I press the turtle key).

To add a double-A feature for this particular locomotive I needed to:

  1. Make sure the general light is on.
  2. Turn on the headlights at cab 1 (auxilary 3).
  3. Turn on the headlights at cab 2 (auxilary 4).
  4. Turn on the shunting mode.

Which exact outputs to turn on for the light will depend on the make of the locomotive. Almost all newer Märklin and Trix locomotives have seperate outputs for the light functions making this a really easy feature to configure.

A rule of thumb: If a locomotive have a 21-pin decoder plug you can almost always make configurations like this, because the lights will be on separate outputs.

Notice: Some locomotives (especially older locomotives that has an 8-pin plug) will have their headlights and taillights linked by the motherboard in the locomotive. These cannot be configured without making modifications to the motherboard. Therefore I normally stay away from making changes to locomotives of this kind. Märklin and Trix locomotives from the "Hobby"-range actually have separate light outputs, even though they only have the headlights and no taillights. These locomotives can be configured as well.

Again: The above guide will work with Märklin retrofit decoders (mSD and mLD) that support mfx. It may also work with the LokSound M4 4.0. It will not work with DCC decoders. To configure function mapping using a DCC decoder, you will have to refer to the manufacturer's documentation for help. The Central Station 2 does, of course, support DCC programming, but it does not have a nice interface for configuring function mapping for a DCC decoder. Usually the decoder manufacturer provides software for programming and setting up their decoders (e.g. the ESU LokProgrammer).

If you have the Märklin Central Station 2, and your locomotive uses a 21-pin decoder, try giving the Märklin decoder family a try, I think you will be happy with the result. I find it to be both fun and easy.

Happy Modelling!