I am using Minecart Mania to build a minecart station on a server. this is what I have so far:
I've already completed 2 stations with little trouble, but this one, the brick isn't doing anything
Once Minecart Mania registers (by doing it once), and accepts your input as valid, and operational, you will see it be bracketed [player:south] - look at the 2 signs in the pic. What I would say, is test it from all angles, and see if you can get each command to  - once it does, it will work every time from then on. If it won't, check your syntax/spelling/directionals/etc - retest till it does
Sometimes I find that if I remove the sign, and simply retype it, it works the next time.