Officers say the beggar threatened the man with violence when he refused to hand over money during the incident in the south concourse of Leeds train station.
It happened at around 2.30pm on Thursday February 18, but police only released details today.
Police Constable Sam Bloomfield, said: “The cleaner was walking into the station to start their shift when a man approached him and asked him for money.
“When he refused the man became aggressive and threatened him with violence before walking off into the station.”
PC Bloomfield said officers have issued a CCTV image of a man they would like to speak to in connection with the incident.
He added: “I believe this person may have key information about the incident and I am calling on anyone who recognises him – or who has information about the incident – to come forward.
“British Transport Police will not tolerate aggression of any kind towards railway staff or fellow passengers, and we will do everything possible to track down the person responsible and bring him to justice.
“If you recognise the man pictured, please contact us.”
Anyone with information is asked to contact British Transport Police on Freefone 0800 40 50 40 or text 61016 quoting reference 254 of 3/3.
Information can be passed to the independent charity Crimestoppers anonymously on 0800 555 111.