What are the top three total number of passengers?
select total_passengers from station order by total_passengers desc limit 3
What are the names and main services for train stations for these?
select name, main_services from station order by total_passengers desc limit 3
What about the names and main services for the train stations with the least 3 number of passengers?
select name, main_services from station order by total_passengers asc limit 3