Here is the full list of all 11 Trainiac achievements.
Kill 100 enemies
Kill 10 enemies
Kill 1000 enemies
Reach the end of a train without taking damage
Die with 0 kills
Survive a train without opening the previous crate
Neutralize 1 car
Neutralize 10 cars
Neutralize 25 cars
Buy everything in the shop
Spot the rare pink car