DeathSpank: Thongs Of Virtue

Here's the best way I've found to accomplish these:

The first delivery is a straight forward run, but is easier if you go ahead and kill all the spiders, then come back for the nitro.

The second delivery, travel ahead and find the shack outhouse. Then go back to the start of the engineer run, go to the right to the first outhouse and transport ahead to shack.

The third delivery - purchase speed and armor potions from the seller by the shack outhouse. Start the run and use both potions. You'll run really fast and be protected somewhat. You'll make this with plenty of time to spare this way.

The cheevo unlocks when you talk to the engineer at the end of the line and you view the cutscene.

After Strumfuquel you will run into an engineer who will ask you to bring dynamite to his conductor. After you bring the explosives he will be found farther down the line later. You must repeat this two more times with explosives and acid, for a total of 3 deliveries. After the third delivery you will find him at the end of the line. If you talk to him Deathspank will study engineering and you will get the achievement. This also opens a cave filled with orques named after the developers.

The first delivery is a straight forward run.

The second delivery requires that you travel around the mountains ahead of time and then teleport using the outhouses.

The third delivery requires that the orque camp be cleared first and then you need to run as straight to the conductor as you can. It is recommended you find him before hand as the acid kills you very fast.