The speed setting of train in the Central Station is easy to complete, but Mobile Station (MS) is not built in the same function.
In MS, which can be adjusted by V max. However, Vmax is not a speed meter but is divided into 255 gradient steps you can accelerate or decelerate.
I made a simple but effective way transferring the Vmax steps as the speed (km/h) accordingly for those who are not affordable to Central Station or focusing on the users using MS.

STAGE 1
I made a simple track layout expanding 5m long around metering by the tape measure. The length is approximately 435m in real distance (5m*87).




STAGE 2
I set the parameter of ACC (Acceleration) and DEC (Deceleration) respectively as 200 and 255. The testing locomotive is DB BR78, therefore, I checked out Wikipedia regarding the information of this locomotive, which describes the maximum speed is 100km/h.





STAGE 3
I set a “start” of the track and started up the locomotive with the knob turning into the right end for getting the large amount of current. The locomotive gradually speed up by means of the setting of ACC. When the loco was being in full speed and was passing through the “start”, I pressed the button of timer until completely running a loop of the layout, I stopped the timer.

STAGE 4
When the parameter of Vmax is set as 150, the running time for one loop is 13 seconds. The real speed is 0.435km*3600/13=120.4km/h around, which apparently is far faster than reality.



STAGE 5
According to the upper parameter, I lowered the Vmax as 131, this time I got the time about 15.41 seconds which means the speed is 0.435km*3600/15.41=101.6km/h close to the reality.



STAGE 6
The Vmax is adjusted a bit to 131 which got the time 15.53 seconds. The speed is 0.435km*3600/15.53=100.8km/h equivalent to the reality.



In spite of deviation generated, the method is available and is recommended to you but you should be aware that the same parameter of Vmax for the different locomotives doesn’t represent the same speed as result of different RPMs of motors, gear ratio and wheel diameters which causes different speed.

Attached is the film with the accurate speed at ACC and DEC mode.

http://youtu.be/JdqOcvWv6Go

Edited by user 20 March 2025 03:15:08(UTC)  | Reason: Not specified

I use a similar procedure, in addition to setting a prototypical top end I also set the speed curve to linear.

Regards,
Roger

It’s difference by use speed steps too on the cabcontrol. I use DCC protocol with 28 speed step which are more comfort for me. Märklin turn knob are not comfort on the MS2.