In the 1950s, Canadian Pacific (CP) operated a robust mail service as part of a nationwide Railway Mail Service that peaked in 1950. This service utilized railway clerks who sorted mail on trains across the country, a service that was essential due to limited road and air infrastructure at the time. The mail service was in decline by the end of the decade due to increased air travel and a new postal code system, and the official service ended in 1971. This was one of CP's busiest short-distance mail corridors - not because of passengers, but because the Ottawa-Montreal line handled huge volumes of mail, parcels, express freight, and newspapers every single night.