How to get Undead Mans Party Bus Trophy/Achievement or Upgrade the Bus in the Call of Duty Black Ops 2 Zombies map TranZit. To Do This you will need to find Three Parts In Four possible Locations.

Bus Parts:
Train Grill (Front) -- Stops zombies from entering through the Front windows.
Ladder (Back Driver-side) -- Allows players to climb to the roof of the bus from outside
Hatch door (Inside) -- Opens the roof for players to enter/leave the bus.

Locations:
1. The starting area between the 2 Metal Doors
2. Bus stop 1 (Diner Area)
3. Bus stop 2 (Farm Area)
4. Bus stop 4 (Town Area)