- Destroy 8 Dominion Trains
- Don't Miss 3 Trains
- Locate Diamondbacks (6)
- Collect Defiler Bone Samples (3) (green dots)
We return to Tarsonis, a planet destroyed in the first game, to take a closer look at what the Dominion is looking for here lately. Matt Horner discovered that the enemy forces are conducting some excavations there, digging to something particularly precious. The mysterious item is supposed to be transported in one of the trains which we will now hunt.
The mission's purpose is to familiarise you with the Diamondback tank - hovercrafts capable of attacking while moving. Their properties will prove very useful in the oncoming train (which will be speeding like crazy) raids. You will see the first three tanks marked on the map in the game. You can go for them [#1] and take them back to the base - there's nothing there to threat you. The location of every single one of them  (five in total) is marked on the guide map. Intercept them at the very beginning, as only the two most distant Diamondbacks are protected by a small, easy to eliminate protection and on your way you will find many resources.
Dominion sends trains [#2] every three minutes through one of the three tunnels in the west . The clock is additionally visible on the screen. As the train appears, his route (always consisting of going through the Center of the map towards the east) will appear on the minimap. There are guard posts placed by the original Dominion stations, so you probably shouldn't get too close and look out for the trains from a safe distance. It's exact the same in the east, but you probably won't venture there. The Center of the map is in fact yours and you can roam it freely, at least until a certain moment, about which I'll tell you soon enough.
You have to destroy eight trains and let three pass, at most. It's easy to guess that each next train will be protected better than the last one and first soldiers will appear with the second one. Not long enough after it derails, you will be warned about an incoming counter-attack, so quickly hide in your base and fight off the incoming (rather small) enemy forces. Before the fourth train appears, Matt will inform you that the enemy has begun securing the track with bunkers. It's indeed a threat, but as long as you don't scatter your forces, you shouldn't have problems with destroying such fortifications [#3].
Dominion will become wiser only after you demolish the fifth train and will send a quite numerous squad of Marauders to patrol the tracks [#4]. They will begin walking in circles round your base and you should of course try to avoid them. If you want to fight them, you should mainly use light units.
The sixth train will move on boosters, so make sure your tanks don't lose it. After the eight one, Dominion will give up on boosters in favour of a strong defence (look out for the tanks) [#5].
Making new Diamondbacks should be your priority in the base. Overall you won't be attacked too often, but doo keep some heavy duty units here (a bunker would come in handy too) to be ready for fighting off the enemy forces. Apart from the hovercrafts, invest in other units, infantry for example. This way you will get rid of the protection and the trains faster.
The second additional task, next to collecting the old Diamondbacks is Defiler Bones. They allow further Zerg research and can be found in the places indicated on the map.