Yup, I've built tons of vinyl garage kits (Godzilla, Ultraman, Gamera, etc) and learned early on (luckily, before I actually painted anything!) that enamel doesn't work on vinyl.
However, for a little drybrushing, I've never had any problems, even on bare vinyl. But if you're gonna cover the whole track, use acrylics.
But tnker101's problem was breakage, not a lack of drying, right?
Hmmmm.....