Auckland police are seeking a man over an assault which left an elderly train worker unconscious in March.
Detective Senior Sergeant Megan Goldie said the 72-year-old train manager was working on a carriage between New Lynn and Fruitvale on 28 March about 4.30pm, when a man and woman appeared to have a verbal confrontation with him.
"The woman has then gotten up and moved to sit across from the victim.
"Seconds later, completely unprovoked, the man has come over and punched the victim a number of times, rendering him unconscious.
"The victim thankfully is doing okay but is understandably shaken by what has occurred and was very lucky not to have received more serious injuries."
The pair got off the train at Fruitvale Station.
Police are releasing a picture of the man, who they want to speak to in relation to the assault.
But Goldie said they also wanted to identify the woman he was with and to ensure she has support available, should she need it.
"The violence shown by this man is extremely concerning and police are very keen to find out who he is so we can hold him accountable."
Information can be provided to police via the 105 reporting line, quoting file number 240330/3374, or anonymously via Crimestoppers on 0800 555 111.