Over a period of about 15 minutes the girls - one aged 14, and two aged 15 - were pinned to the floor of the carriage and indecently assaulted by three youths and only managed to get help from rail staff once they got off the train at Crosby.
The incident happened on Sunday evening.
Station staff comforted the girls, while colleagues along the line held up the train at Seaforth station. The train's doors were locked while they waited for police officers to arrive. However, the boys, aged between 10 and 16, wedged open a door on the track side of the train and escaped across the lines despite the danger from a live rail carrying 750 volts.
Merseyrail Electrics' staff were also shocked that none of the other passengers had stepped in or even pulled one of the communication cords situated at every door.' We are amazed,' Catherine Murphy, of Merseyrail, said. 'Just shocked, surprised and stunned that no one tried to help these girls who were in obvious distress.'
Yesterday, British Transport Police CID officers were interviewing the girls separately in an effort to get a clearer picture of the incident. They were following up several leads.
Officers also said that a number of people who were on the train had come forward with information after an appeal for witnesses, though they still wished to contact an Asian man who was sitting near the girls when they were attacked.
The 7.19pm Southport to Liverpool train is estimated to have had at least 200 passengers on board as it made the 40-minute journey from the popular resort on the sunny Bank Holiday Sunday.
The girls, all from the Crosby area, were attacked shortly after the train left Southport and were subjected to their ordeal until they were able to escape at their home station. Police said they were shaken and distressed by the