Table: train_schedule_2
Columns: departure
going_to
calling_at
arrival
operator

Question: How many trains call at Castor, Overton, Peterborough East and are operated by LNWR?
SQL: SELECT COUNT("arrival") FROM train_schedule_2 WHERE "operator" = 'LNWR' AND "calling_at" = 'Castor, Overton, Peterborough East'