Here is the full list of all 27 Pandemic Express - there are Zombie Escape achievements.
Kill the last human in the match
First killed zombie
Hop on the train for your first time
First killed human
First successful escape
Complete tutorial
First match
Open airdrop for your first time
Kill human with a mimic mine
Kill a human with a bomber
Kill for mimic on any vehicle
Kill zombies on any vehicle
Escape with the radio in the hands
As human, blow up another human with a bomber
Take home at last on zombies
Take home at last on a human
Equip 'Safety One' set and play with him
Equip 'Lover' set and play with him
Equip 'Arrogant One' set and play with him
Equip 'Doubtful One' set and play with him
Equip 'Leader' set and play with him
Equip 'Hopeful One' set and play with him