Question: What is the main service for the station with 14.849 million passengers 2011-12? 
SQL: SELECT "Main Services" FROM "1-18118221-1" WHERE "Total Passengers (millions) 2011–12" = '14.849';

Question: What is the lowest rank of Gatwick Airport? 
SQL: SELECT MIN("Rank") FROM "1-18118221-1" WHERE "Railway Station" = 'Gatwick Airport';

Question: Which location has 103.534 million passengers in 2011-12? 
SQL: SELECT "Location" FROM "1-18118221-1" WHERE "Total Passengers (millions) 2011–12" = '103.534';

Question: How many annual interchanges in the millions occurred in 2011-12 when the number of annual entry/exits was 36.609 million? 
SQL: SELECT "Annual interchanges (millions) 2011–12" FROM "1-18118221-1" WHERE "Annual entry/exit (millions) 2011–12" = '36.609';