For this achievement, you'll need to get rid of all the things blocking the train on the tracks. The tracks run from the edge of Strumfuquel all the way to the end of the desert. Even though it seems like a long way, there are only three quests that need to be completed. They are:
Nitro Run: Before you talk with the first conductor, make sure to clear out the tracks of all enemies. When you accept this quest, you're given "nitro" and you can't use your weapons, or get hit, otherwise the "nitro" will explode. When the track is cleared up to the first engineer, grab the 'Nitro" and run to the engineer.
Dynamite Shuffle: This one is a little tricky. It's a short distance, however, you'll need to use the Outhouses. When you get to the blockage, you'll notice that the engineer is on the other side of the rocks. even though you can go around with the dynamite, it would take too long and will explode. Once you have the side path already discovered, get the dynamite from the second conductor, use the outhouse to the right of the second conductor and travel to the closest Outhouse on the other side of the rock.
Acid Reflux: Use a Nature resist potion to carry the acid safely to the engineer.
After you've completed all this, follow the tracks all the way down to the end of the map and you'll see an engineer that is not highlighted. Walk up to him and talk and you'll enter a cutscene with DeathSpank getting an education. After the cutscene is finished, the achievement will unlock.