Here is the full list of all 12 Transport Giant achievements.
Finished USA campaign
Played for at least 10 hours
Earn at least 100,000,000
Played for at least 1 hour
Possessed 25 vehicles at a time
Possessed 10 vehicles at a time
Play for at least 50 hours
Play for at least 75 hours
Play for at least 100 hours
Finished Europe campaign
Finished Australia campaign
Exceed demolition costs of 1,000,000