I am starting a new thread as this situation has been noted in several threads.
On page 22 of the set manual at the top under troubleshooting it says "The locomotive stopped dead." It says the locomotive is equipped with "motor lock out" technology. I suggest those of you who have had you engine stop read that section.
The only problem I have had with mine stopping is where it found 2 imperfect spots on my Gilbert track at very low speed. A little track correction and it went fine.
Mine pulled the five cars and three of my Union Pacific heavyweights of the same type easily. I used a 30B with 15 volts and the FlyerChief.