The book was set in Little Fork, Minnesota, with main characters Kristina Haugen, Martin Stensby and Gena and Ola Bye. Kristina has arrived from Norway with her niece to join her brother. When he is not at the station to meet her, she is taken in by the Byes.
Could it be “Love Song” by Karen Peyton, 1964? There’s a listing on LibraryThing that lists the characters of Christina Haugen, Martin, Finn Haugen, and Elise, and Little Fork is listed as an important place. The first line is listed as: “Christina’s anxious eyes searched the length of the railroad station platform once again – slowly.”
Thanks! that’s the book!