"Blue Arrow" BCFe 4/6 # 736 of the BLS foundation is on the way from the home base Burgdorf to Olten near Wynigen. This iconic vehicle from 1938 ran a birthday party train on this wonderful summer day, from Olten via Solothurn-Biel-Sonceboz-La Chaux de Fonds-Le Locle-La Chaux de Fonds-Chambrelien-Neuchatel-Biel-Solothurn-Olten.