Call Back the Past — Jean S. MacLeod

"When Janet boarded the fabled Orient Express for Austria, she was hoping to fulfill a dream for her godfather. She was to locate his long-lost love, a woman believed to be living in Salzburg. On the train, she met a flint-eyed stranger, a man who introduced himself as Stephen Kempson but revealed little else. Once in Austria, he became a puzzling mix of warm friendliness and cool reserve--at least as far as her quest was concerned. And at some point, she was never sure just when, her mission of love took a turn in her own direction."