If a minecart is at rest on a deactivated powered rail, simply powering the rail will not make it move. The minecart must be kickstarted somehow, e.g. by a player pushing it in the desired direction.
I'd like to make a traditional train station, where the carts stop briefly at a platform before speeding away. However, due to this limitation, the process can not be fully automated.
What are some techniques to start minecarts from a full stop without any direct influence by the player? If possible, I'd like to avoid sloped rails because they look bad next to a platform.