CREATE TABLE "table1_12221135_3" (
  "departure" text,
  "going_to" text,
  "calling_at" text,
  "arrival" text,
  "operator" text
);

Question: How many trains call at Castor, Overton, Peterborough East and are operated by LNWR?
SQL: SELECT COUNT("arrival") FROM "table1_12221135_3" WHERE "operator"='LNWR' AND "calling_at"='Castor, Overton, Peterborough East';