All the warnings you have right now were given to you automatically after you derailed a few times due to too high speed (each time you've got +20% of warnings given by the server). You can check that in private messages on forum, after every incident server is sending you a message that you got +20% at your account. To avoid getting these punishments, you need to pay more attention to the speed limits on the tracks. If your warning level is 40% or above, the driver mode is locked until it drops under that value (5% every 24h). You can check this information in your profile on forum.
If you want to do more training on braking, you can try singleplayer scenarios, where even if you derail, you shouldn't get punished.
Hope that everything is clear
~KMS