Well I made a roller coaster to the max height and rode on it but when I got to the bottom I made it so you were supposed to fall out of the world so you didn't have to walk back, so when I got to the end I just stopped and you could hear the new cart noise and so I broke it and it didn't stop for a good 5 minutes then I just hit (esc) and it stopped I have added some pictures for you to see if you want to recreate this to try and fix it