The husband and wife were travelling on a train from Leeds to Pontefract Monkhill on Saturday, October 10 when a group of three men and a woman got on at Glass Houghton.
They abused the man about his ginger hair and glasses and he told them to leave him alone.
The gang then became aggressive and as the couple went to get off the train at Pontefract Monkhill, one of the men punched the woman, 47, in the chest.
They then followed the victims after they got off the train at Pontefract Monkhill at around 9.30pm and attacked them from behind.
The man, 48, was knocked to the floor and kicked by the male members of the group.
When his wife attempted to stop them, she was pushed away and then attacked by the female member of the gang.
PC Sarah Donnelly, from the British Transport Police, said: “Officers were called to the incident and attended but the group had fled the scene.
“This was a violent and unprovoked assault on a couple who were simply returning from a day out. If you know the people pictured, please contact us.”
Police have now released CCTV images of three men and a woman they would like to speak in connection with the assault.
Anyone with any information should contact British Transport Police on 0800 405040 or or text 61016, quoting reference PSUB/B2 of October 10.
People can also give information, anonymously, on 0800 555111.