Question: Show all train names and times in stations in London in descending order by train time.
SQL: SELECT T3.name ,  T3.time FROM train_station AS T1 JOIN station AS T2 ON T1.station_id  =  T2.station_id JOIN train AS T3 ON T3.train_id  =  T1.train_id WHERE T2.location  =  'London' ORDER BY T3.time DESC