Peter Mussett, of no fixed abode, has been imprisoned for 10 months after sexually assaulting a 12-year-old girl and a woman on the Docklands Light Railway (DLR) on the same day.
He was also sentenced to a seven-year sexual harm prevention order banning him from using the Tube and DLR while under the influence of drink or drugs.
He must also only travel using an Oyster card registered in his name and with a police station
He was also ordered to pay hundreds of pounds in compensation to both victims.
At an earlier hearing Mussett pleaded guilty to two counts of sexual assault on a girl under 13 and one count of sexual assault on a woman.
Detective inspector John Justice said: “This sentence reflects the seriousness of Mussett’s offending. I believe he went out on public transport that evening with the sole purpose of targeting and assaulting women for his own sexual gratification.
“Mussett’s attack on a woman only stopped when she challenged his behaviour. Mussett’s second victim was travelling home on her own when she was assaulted. Mussett indecently touched her on two separate occasions as she stood in the carriage.
"This was understandably an incredibly frightening experience for the young girl. I would like to thank both victims for their bravery in reporting the matter to police and for their co-operation throughout our investigation.
“We will always fully investigate all reports of unwanted sexual behaviour on public transport. The more victims who report offences to us, the more we can do to catch persistent offenders and bring them to justice through the courts.”