The victim, a man aged 46, boarded the service at York railway station.
Two women got onto the train at Leeds and sat opposite the man, according to British Transport Police (BTP).
After insulting, swearing and making racial comments to towards the victim, he was left covered in beer after they threw a can at him.
One of the women then made threats towards the man, and said she wanted to fight him.
Both offenders left the service at Huddersfield, BTP said.
BTP has today released CCTV images of women they are tracing in connection with the offences, which happened October 16 at about 4.30pm.
Anyone with any information is asked to contact BTP on 0800 40 50 40, or text 61016 with reference 361 of October 16.