Here is the full list of all 10 Bus Tycoon ND (Night and Day) achievements.
Your company is in service for 50 days!
Your company owns 15 buses!
Your company owns 10 buses!
Your company is in service for 20 days!
You can buy a hydro bus!
You can buy new biofuel buses!
Your company is in service for 10 days!
You can buy an electic bus!
You can buy new diesel buses!
Your company owns 5 buses!