Operations on the Koralm line began with multiple services shortly after its official opening on 12 December 2025. ÖBB reported that around 30 trains carried roughly 10,000 passengers through the line in Carinthia and Styria within the first few hours. The connection between Graz and Klagenfurt is timetabled at approximately 41 minutes and includes both long‑distance services and new InterRegio offerings. ÖBB has increased overall train services for the upcoming Christmas and New Year period, with more than 60 additional connections and about 23,000 seats scheduled. The operator is recommending that passengers reserve seats in advance, with reservations available at modest fees and with flexible cancellation terms.
Alongside the start of commercial services, the first fully modernised Railjet trainset, named “Koralmjet,” completed its inaugural passage through the new tunnel sector.
On 13 December 2025, the Freiwillige Feuerwehr Gussendorf (Gussendorf volunteer fire brigade) reported a significant emergency response linked to the Koralm Tunnel. At 13:55 local time, firefighters were alerted to a report of smoke at a tunnel portal on the same day as the railway’s inaugural runs. Thirteen crew members initially responded with a rescue and firefighting vehicle (RLFA 2000) and a multi‑purpose vehicle (MTFA) to manage traffic and ensure unimpeded access for additional responders to the designated rescue point at West Styria station.
The situation did not involve a train or passengers; ÖBB later characterised the incident as a dust cloud. The fire brigade stood down and returned to base around 18:00 after a major operation involving 103 firefighters with 32 vehicles. Additional support was provided by the Austrian Red Cross, the Green Cross, police units, ÖBB officials, and a specialised rescue train from Werndorf.