The two accused, a sub-inspector and a constable with the BSF, and the victim's family were in the same coach of the Anand Vihar Express when the incident took place, they said.
The BSF officials, both posted at Bhuj in Gujarat, had boarded the train from Jalandhar in Punjab where they had come to attend a national level sports championship.
In an FIR, the girl's father has alleged that the two BSF officials started molesting his daughter when the train was about to reach Ambala Cantt railway station.
The police immediately nabbed the molesters and recorded the statement of the victim girl.
According to police, the victim and her family were returning to their home city Meerut after visiting Vaishno Devi shrine in Jammu and Kashmir.
Senior BSF officers have been informed about the incident, said Niyaz Mohammad, Sub Inspector, Ambala Railway Police.
BSF officials have denied the charges and said that there was a minor altercation between the personnel and the girl's father and that the two had been falsely implicated.
