I know there are fine-scale wheels for HO and O scale, don't know about N. They would have much finer flanges and treads than the "Standard" wheels. If there's no major visible difference between the wheels on the car that derails and you others then that's not the problem.
Here are some major causes of derailments caused by the car (since the other cars work OK I'll assume the problem isn't the track):
Wheelset out of gauge. Check the wheelset with your NMRA standards gauge. If you don't have one get one! If the wheelset is out of gauge replace it.
Wheelset is otherwise a problem. Maybe one wheel wobbles as it rolls. Remove each wheelset and roll it on a flat surface, if any wheel wobbles replace the wheelset.
Binding in the trucks or wheelsets. Check the truck and wheelset for flash (that thin plastic that seeps between the parts of the mold). Also make sure the trucks can turn freely, the screws aren't too tight. Also generally only one truck should be able to wobble, the other should turn but not wobble.
Make sure the truck or some other part of the car isn't hitting anything like a ladder on the car, or the switch machine or scenery.
Make sure the car is weighted properly, if it's too light it can derail.
