A landslide today sent one carriage of a Swiss passenger train plunging into a ravine and left another hanging from the rails, the BBC reports. Officials are calling it a "serious" incident, though the number of casualties isn't known. The RT network reports 200 passengers were on board; a police spokesman says those with injuries have been taken to the hospital, though some had to be rescued via helicopter. The Rhaetian Railway train derailed on its way to Chur from the St. Moritz ski resort in a wooded area near Tiefencastel, reports SwissInfo. The line is frequented by tourists. Heavy rain overnight is being blamed for the landslide.