How to find maximum and minimum speed

Decoder speed profile


Speed ​​profile

Here it is described how to set the minimum and maximum speed of a locomotive so that on the one hand it runs slowly but safely and without jerking at speed level 1 and at the highest speed level it just reaches the prototypical top speed. Since most vehicles drive too fast, you can set a more even use of the entire control range.


The driving behavior of a locomotive is determined by the good engine and gearbox, as well as how much voltage is fed to the engine in the individual speed steps.

Everyone knows the problem, the beautiful model of the BR 44 from XYZ. It only starts at speed level 4 and already reaches its exemplary top speed of 80 km / h at speed level 16. The speed levels 1-3 and 17-28 are therefore not usable, and because we only have 14 for the entire speed range with these settings Using speed steps, sensitive control is also not possible. However, you can set this by programming the decoder so that the entire control range of 28 speed steps is available for the locomotive.

Unfortunately, these settings for the various digital protocols and decoders are sometimes configured differently from manufacturer to manufacturer. Since I am a DCC driver myself, this part is a bit more detailed. Many manufacturers also offer multi-protocol decoders. These can then possibly be configured in various ways. Here you should read the decoder description very carefully before turning the settings.

But don't worry, as far as I know all newer decoders have a reset option, which returns the adjusted decoder to the delivery state. Please consult the decoder manual for this.

Decoder according to NMRA

This includes almost all DCC decoders.

With the NMRA compatible decoders, the speed settings can be made via CVs 2 (min), 6 (mid) and 5 (max). Simply put, one can say:

  • The value in CV 2 determines how fast the locomotive drives at speed level 1.
  • The value in CV 6 determines how fast the locomotive drives at medium speed.
  • The value in CV 5 determines how fast the locomotive drives at maximum speed.

All other speed steps are automatically set with intermediate values ​​by the decoder.

With the ESU Lokpilot v3 the default values ​​are preset to 3/22/64.
With Lenz decoders the default values ​​are preset to 0/48/255.
Here you can already see that the ESU has the value range 1..64 as the setting scale, while Lenz uses the value range 0..255 for the same function.

Setting the minimum speed

First increase CV2 until the locomotive runs smoothly at speed level 1 without jerking. CV 2 determines how high the voltage for the locomotive engine is at speed level 1. And with it how fast the locomotive drives at this speed level. For example, I only have one locomotive where I had to increase the value (to 6). Most locomotives still run without problems even at lower values.

Setting the maximum speed

Then the maximum speed of the locomotive (at max. Speed ​​step) is set with CV 5. Since actually all models drive too fast, you can usually reduce it properly here. I do it in such a way that I carry out a single measurement run with TC at maximum speed and then reduce the value in CV5 until the locomotive only reaches the exemplary top speed. With the ESU Lokpilot V3, I turned down from a maximum of 64 on many locomotives down to 24 until the top speed was right.

Setting the medium speed

Now the average speed has to be set in CV6. here you can for example. set the mean value from CV2 and CV5, then you get a linear speed profile. Or you can enter a slightly smaller value. This means that the locomotive can be controlled more sensitively in the lower speed levels, but that's just a matter of taste.

With these three values, the locomotive has been programmed with exemplary (even) driving behavior over the entire control range.

And only now does it make sense to completely measure the locomotive.

SX decoder

MM decoder

Warning: decoder types

  • Please pay attention to the values ​​I have given for CV 2/6/5 !!!!
These are only valid for the decoders mentioned.
If you have other decoders, you have to configure them differently.
It is best to read the decoder manual.
  • You also have to pay attention to the range of values.
Some decoder manufacturers allow values ​​from 1..64, others 0..127, or 0..255

more settings

Start-up and braking delay

There is information about this in the article Decoder: acceleration and braking delay

Professional attitude

Finally, it should be mentioned that many decoders allow manual setting of the complete decoder characteristic. I personally tried to get the most out of the driving characteristics of a locomotive. I've decided for myself that the effort is usually not worth it. Most of the time you only improve your driving behavior if you don't know exactly what you are doing.

For this reason I will not describe it here either.

CV 5 cannot be set

Some decoders have a "child lock". If this is set, the CVs can no longer be adjusted. In the forum it was reported that some Roco decoders have activated the child lock in CV 56. A value of 0 deactivates the child lock. These decoders have found their way into some Roco starter sets, for example. But be careful: CV 56 has a different meaning for other manufacturers. For example with the ESU Lokpilot v3 this is a setting for the load control. So first look at the manual before adjusting.

CV 6 does not exist

The ESU Lokpilot Basic decoders have no setting option for the average speed via CV 6. Here you can only ignore this or install another decoder. The important settings via CV2 and CV 5 are usually sufficient anyway. As far as I know, this only applies to older ESU decoders. And here again the reference to the explanations in the decoder manual.

Good luck - DieterN 11:05, Jan. 26, 2010 (UTC)

Based on a hint from the user area, I am adding the following to the article:

  • Information on the subject Brake compensation can be found in the FAQ under measuring

Wohlmannstetter 19:21, 29 Apr 2010 (UTC)

editorial processing: Wohlmannstetter (discussion) 16:57, 7th Mar. 2021 (CET)