Italy's national fire service, the Vigili del Fuoco, said around 6 p.m. that a locomotive and first carriage derailed on the regional train line between Venezia and Trieste in the northern part of the country.
The train was traveling near Bivio di Aurisina when it hit the boulders with 22 passengers on board.
Video released by fire officials showed firefighters helping people off the train through rear doors.
Boulders also could be seen on the tracks as first responders surveyed the scene.
According to local media, recent improvement work had been carried out in the area near the landslide.
No one was injured in the incident, fire officials said.
Rail traffic was suspended through the area, with interruptions expected to continue Tuesday, according to local media.
Riccardo Riccardi, the vice president of the regional government of Friuli-Venezia Giulia, praised the work of first responders on Twitter.
"For the transhipment operations, thanks to the firefighters and the volunteers of the Civil Protection, who immediately took action to support the passengers on board, all fortunately unharmed," he wrote.