British Transport Police are today releasing CCTV images following a report of grievous bodily harm on a train at Pontefract Monkhill railway station in West Yorkshire.
The incident happened at 8.59pm on Friday 16 October.
A train guard was attacked, suffering a broken finger which required surgery.
Officers would like to speak to the people in the images who may have information that could help their investigation.
Anyone who knows them is asked to contact BTP by texting 61016 or by calling 0800 40 50 40.
In both cases, quote reference number 587 of 16/10/20.
Alternatively, call Crimestoppers anonymously on 0800 555 111.