A 20-year-old woman was allegedly gang-raped on Friday by robbers on the Lucknow-Mumbai Pushpak Express, PTI reported.

The attack occurred between the Igatpuri and Kasara railway stations in Maharashtra on the route of the Central Railways.

The Mumbai Government Railway Police have arrested four of eight accused persons. The accused persons also robbed 15 other passengers, according to The Times of India.

Mumbai Government Railway Police Commissioner Quaiser Khalid said that the accused boarded the train at Igatpuri town in Nashik district on Friday night, PTI reported. They allegedly raped the woman when the train was passing through a mountainous area.

When some passengers tried to stop them, the accused attacked them with sharp weapons, injuring six, according to NDTV.

However, some passengers managed to apprehend two of the accused persons and handed them over to the Government Railway Police when the train reached the Kasara station near Mumbai, according to The Times of India.

The Government Railway Police, which have formed a team to investigate the crime, caught two more men on Saturday.

“The victim has been taken for medical examination by our officer,” Khalid said. “We are collecting all evidence. The accused are being questioned by our team. We are checking their previous records.”

Khalid said that the accused men had stolen items, mostly mobile phones, worth Rs 96,390. The police have recovered items worth Rs 34,200.

The police have registered offences against the accused men under the Indian Penal Code sections 395 (dacoity), 397 (robbery, or dacoity, with attempt to cause death or grievous hurt), 376 (gang rape), 354 (assault), 354(B) (assault intending to disrobe or compelling a woman to be naked).

The accused have also been charged under sections of the Railways Act.