Phillip Clive Butterworth, aged 70, of New Oceans Hotel, Blackpool, pleaded guilty to sexual assault and was sentenced to 27 months behind bars at Preston Crown Court on Monday, 7 December.
He was also issued with a restraining order to prevent him from contacting the victim and placed on the sex offenders register for 10 years.
The court heard how on January 9 this year, Butterworth approached his victim as she waited for her train at Blackpool North station, asking her if she was travelling alone.
Once she boarded the train, Butterworth sat down next to her and began subjecting her to lewd sexual suggestions, trapping her in her seat for the entire 25 minute journey, while touching her inappropriately.
The victim was so terrified by Butterworth that she sent text messages to her mum saying ‘help me’ and asking for advice on what to do.
DC Chris Biggs said: “This was a vile and disgusting assault on a vulnerable young woman who was left terrified by Butterworth’s disgusting and inappropriate behaviour.
“The sentence handed down to him reflects the severity of his actions and will give the victim some comfort as she attempts to recover from this incident, which has left her deeply traumatised.
“Thankfully incidents like this are rare, but anyone travelling on the rail network can text us discreetly on 61016 if they are concerned for their safety or need to report an incident.”