To get the Achievement and/or PS3 Trophy you must do the following. The Achievement/Trophy is called "Dev Graffiti".

1. Finish up Wellsping and goto Subway Town.
2. Once your at Sub Town, talk to a man named http://rage.wikia.com/wiki/Dietrich.
3. He gives you the quest " http://rage.wikia.com/wiki/Abandoned_Distillery_(Quest) "
4. Goto the Quest area and follow the 'path'.
5. Watch this video ( Covers Step 4 and the rest )

http://www.youtube.com/watch?v=fotc_dUuWzU