Which location has the most number of train stations?
select location, count ( * ) from station group by location order by count ( * ) desc limit 1
What is the total number of passengers do train station in london has ?
select sum ( total_passengers ) from station where location = 'London'
What is the number of platforms does train station in london has?
select sum ( number_of_platforms ) from station where location = 'London'
What is the name of the train station in londom?
select name from station where location = 'London'
What is the main service of  train station in london?
select main_services from station where location = 'London'