An engine of Hyderabad Express derailed near Monkey Hill station in Khandala ghat on Wednesday noon.
The Khandala ghat section is considered a tough gradient ghat. (File)
Railway sources said all passengers are safe.
The mishap took place around 3.30pm, when the train was crossing the Khandala ghat section, which is considered one of the tough gradient ghat, via the middle line.
A boulder which came off after a landslide came on to the tracks, said railway officials.
According to railway sources, the train was running about 36 minutes behind schedule when it left from Karjat.
The accident may affect running of trains on the Mumbai-Pune route.
This is the second such derailment of a long-distance train in less than 20 days.