It will fade, it will scratch, if the surface was oily it may peel, but once completely dry (about 2 days?) acrylics won't wash off.
enamels are a little tougher.
This station was painted many years ago with cheap craft shop acrylics. It's even spent 2 winters outdoors. The paint has held up better than the bare Piko plastic on the roof which is getting chalky.
I even painted a church with Bic Whiteout once. Some of it peeled, but that's just made it look even more 'weathered'.... (the odd side window is a solar panel for lights)