Dear Rollie, Frans Olov Carlsson was indeed a Titanic passenger. He was going to America to be a ship's officer on one of the American Line's ships. He was 33 years of age, and was from Värmland, a province in the west of Sweden. There is a memorial plaque in his parish church.
The Frank Carlson who had an American family was probably one of the numerous people who later claimed they were going to sail on the Titanic but didn't
Best regards,
Peter Engberg-Klarström