Enchants on minecart wears off when placing it on rail(s).

1. Give yourself sharpness 5 (or any enchantment that can be applied using an anvil) enchantment book.
2. Give yourself a minecart.
3. Put the enchantment on the minecart using an ANVIL.
4. Place some tracks, GO TO SURVIVAL MODE, then place the minecart on them.
5. Get back the minecart, you will see any enchantment is gone.