The man, who was travelling on the 20.18 Glasgow to Alloa service on 29 December, was punched by the group of five men.
The assault took place shortly after 9pm in the vicinity of Larbert.
It left the man with a cut to his head and bruising to his face.
British Transport Police is investigating the hate crime and appealing for witnesses.
According to police, the group departed the train at Stirling station. One of the men is described as being of stocky build with short brown hair and was wearing a khaki body warmer.
A second suspect is described as being around 50 years of age and wearing dark clothing and a third was around 5'10" in height and wearing a quilted jacket.
Derek Jackson, the investigating officer, said, "The victim was subjected of a deplorable attack and I am anxious to trace those responsible as a matter of urgency. If you have any information please come forward."
It was the second hate crime on board Scotrail trains travelling in the Stirling area that night - although both incidents are not thought to
Around 8.20pm, two men are reported to have racially abused a mixed-race man and another couple (a white woman and black man) on the 20.44 Glasgow Queen Street to Dunblane service.
The two men responsible, who also alighted from the train at Stirling, are both described as being aged between 30 and 40 years, with very short hair and wearing dark clothing.
Anyone with information should contact the British Transport Police on 0800 40 50 40 or information can be given anonymously to Crimestoppers on 0800 555 111.