minecart bug

ok so when I'm on realms and i created this roller coaster system. well sometimes at random spots of the roller coaster, my mine cart will start bugging out by wiggling crazy (so fast it gets you motion sick and impossible to see. and then you start going backwards and repeat. but when somebody sees you they don't see you wiggle and go backwards they see you go straight like nothing happened. so if you start to bug and wiggle and you break mine cart, it disappears. well apparently it'll appear broken where the other person sees you and where you should've been if you kept going fine. sometimes the mine carts spawn in the middle of ocean and i waste to many mine carts and can't really use them. PLEASE FIX!
THANK YOU, JERRY50TH