Personally, depending on the situation I'd interpret 2) either as a general statement ("I (always) walk from the station to school") or as a general future plan ("I will walk from the station to school").
1) is a process that is going on at the moment of speaking, and will probably go on until the goal is reached. ("(Right now) I am walking from the station towards school.")
Let me know if you need me to provide more context or examples :)