Two things immediately come to mind. Dirty tracks & especially contaminated center rail. Another is the loco being new, it takes a while for the anodizing on the new wheels to wear off & once that has happened you get better contact. Does this occur at a particular spot or is it random any where on the layout?

Hello,

Many thanks for your inputs. I am using Marklin C track 3 rail.

Track is clean and center rail well. I know this because when the loco stops as mentioned above the sound functions and lights stay, they don’t stop. So this mean energy is going to the loco, ut the motor at VERY low speed regime just stops.

It happens randomly ( depends whey I decide to stop the loco ).

This is a classic symptom of poor contact on the motor brushes. Check to see whether the brushes might be worn down. If they are OK then it could be the tension on the springs that hold the brushes against the motor commutator.

To check if this is the case, run the loco with the body off. When the motor stalls at low speed prod the brushes with a toothpick or matchstick. If I'm right the motor will start turning.

You can gently bend the springs to get better tension.

Hope this helps.

Ok if the sound is on when the loco refuses to move all of the above we mentioned is out of the window. First & cheapest option is to retract the springs that hold the brushes & disassemble the motor. Is the brush area clean or contaminated? If contaminated you have oiled an area that really does not need oil.I personally never put oil on that end. I only put a dab of oil on the gear end. If dirty clean & resemble making sure brushes have free travel.You mentioned the loco was new so contamination is unlikely but must be checked. If the loco demonstrates this behavior again then we are looking for wires with bad contact or at worst the decoder can have an issue. I feel this is something simple you can sort out. Had this been a C-Sine motor issue it would be an electronic issue. Please keep us informed of your progress. Pictures are welcome & can often solve the riddle.

That would be much appreciated. New brushes & a clean up of the commutator would not go astray. Make sure the brushes can freely move on the brass housing & there is no snagging. As I mentioned before no oil on this end. It just leads to a gritty grimy paste. #601460 Motor brush replacement. One other thing not mentioned is the possibility of a wire off / broken on the armature. It will still run but will not start up by itself & it will not run as it should. But I don't believe that is your issue.

I've been having a similar problem with a Loco. The Loco got really hot and also the decoder.
I found out it had to do with the magnet. The plastic that keeps them together was very loose.

After changing the magnet to a new one I didn't get any more problems. The Loco was brand new.

Update:

I changed the brushes and no change, the problems still appeared when running long time and trying to stop.

So I changed magnet, rotor and brushes all together with kit 60941 arrived today by post and so far so good. After running long time it does not show the issue again.

Lets see after more hours of operation if the problems comes back.

There was after 40h from new but when I opened the motor today to replace it after 10h from first motor inspection there was very little build up.

I guess the old rotor commutator had some sort of problem.

So far so good the loco has not shown any sign of the problem with new engine parts.