route passed entirely south of Austria's postwar borders. The service via Italy was known as the Simplon Orient Express, and it ran in addition to continuing services on the old route. It soon became the most important rail route between Paris and Istanbul.

The 1930s saw the Orient Express services at its most popular, with three parallel services running: the Orient Express, the Simplon Orient Express, and also the Arlberg Orient Express, which ran via the Arlberg railway between Zürich