The suspect was travelling on board a Glasgow Queen Street to Edinburgh Waverley service on Saturday, May 5 when he began shouting and swearing at his victim.
A train guard who intervened during the incident, which took place at 7.40pm, then became the target of the abuse.
The suspect then left the train at Linlithgow station. He is described as white, well-built and approximately 6ft with shaved red hair, ginger stubble and multiple tattoos on both arms.
He was wearing a grey t-shirt and jeans at the time of the incident.
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Anyone who witnessed this incident or who recognises the man’s description is asked to text 61016 or call 0800 40 50 40, quoting reference 582 of May 5.
Alternatively, contact Crimestoppers anonymously on 0800 555 111.