Show all train names and times.
select name, time from train
Show the results only for trains in stations in London.
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 them in descending order by train time.
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