After a construction period of two and a half years, the Ruckhalde Tunnel on the new railway line from St. Gallen to Riethüsli was opened for traffic in early October 2018. On the opening day the Appenzeller Bahnen (AB) celebrated the commissioning with about 6000 guests.
According to the statement of AB, 63 million Swiss francs were invested in the building of the the 725 m long, single-track Ruckhalde Tunnel, which is thus the most important and largest construction project in the modernisation of the Appenzeller Bahnen.
The tunnel replaces the old 940 m long rack section in the Ruckhalde and thus enables the introduction of a fifteen-minute cycle between Appenzell and St. Gallen. After the preliminary works had begun in December 2015, the excavation of the tunnel by hydraulic excavator started from the north portal in July 2016, to be replaced by drill and blast from August. The opposing drive started at the end of the same year, in November. The breakthrough of the Ruckhalde Tunnel was celebrated in July 2017. Beginning in February 2018, the inner lining and the installation of the railway technology was tackled.