Kwamin Mercer, 39, sexually assaulted five women on trains in a series of attacks across two days in the West Midlands last year.
His first offence, on the evening of 3 September, happened on a train as it left Birmingham. He approached a lone woman and sat in the seat opposite her before leaning forward and touching her inappropriately.
The woman immediately moved away from Mercer, who then put his hands in his trouser pockets and appeared to touch himself.
The following morning, between 7am and 9am, Mercer sexually assaulted four more women by touching them inappropriately between stations across the West Midlands. One of the victims was a 15-year-old girl travelling to school with a group of friends.
Mercer was jailed for 48 months at Birmingham Crown Court and issued with a Sexual Harm Prevention Order for 10 years.
The order bans him from sitting next to females he doesn't know on public transport and from travelling on the rail network, Underground or DLR in the UK without a valid ticket purchased by a bank card registered to him.
Mercer, of Corporation Street, Birmingham, had pleaded guilty to six counts of sexual assault by touching, one count of outraging public decency, one count of common assault and one count of committing a common assault with the intention of committing a relevant sexual assault.
All the victims reported Mercer’s behaviour to British Transport Police using its 61016 text-to-report service. He was arrested and charged after a BTP investigation.
Pc Jade Ledbrook said: “Mercer showed himself to be a repeat offender over those two days – his conduct was repulsive as he repeatedly targeted women for his own sexual gratification.
“Thanks to the victims who reported his vile actions he’ll now have plenty of time on his hands in prison to reflect on his predatory behaviour.
“The impact Mercer had on his victims has been significant, however the women showed tremendous courage in reporting him to us using our text service.
“I would urge anyone subjected to, or witness to, unwanted sexual behaviour on the railway to do as the women in this instance did and text us on 61016. In an emergency, always call 999.
“No report is too small or trivial, and we will always take you seriously. Everyone has the right to a safe journey.”