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