This story was first published on Dec 8, 2015, and updated on Jan 6, 2016.

SINGAPORE - A regular serviceman, who punched a man once in the left eye in the MRT train, was on Tuesday (Dec 8) fined $3,000.

Kelvin Poon Kai Chen, 22, admitted hurting Mr Choo Chin Huat, 35, a Malaysian principal engineer, in the train going from Bedok towards Kembangan on Feb 6 this year.

Deputy Public Prosecutor Kong Kuek Foo told the court that at about 5pm that day Poon, a lance corporal, and his girlfriend were waiting for the train at the Bedok station.

Poom claimed that when the train arrived, Mr Choo jumped queue and boarded the train ahead of them. A dispute broke out between Poon and Mr Choo, during which Poon pushed the victim's hand away. The victim purportedly challenged Poon.

Two commuters, both students, tried to separate them and calm Poon down by saying "chill'' and "cool down".

Suddenly, Poon punched Mr Choo once in his left eye, damaging his spectacles and hurting his left eye.

Poon was then restrained and escorted off the MRT train by the station staff at Kembangan station.

Mr Choo sought treatment at Changi General Hospital. He complained of headache, pain around his left eye and giddiness. He was found to have an eye contusion.

Poon's lawyer, Ms Alice Tan, a Criminal Legal Aid Scheme (Clas) Fellow, said in mitigation that Poon was most remorseful for what he had done and, on hindsight, realised it was foolish.

She said he has an unblemished record and is looking forward to a fruitful and meaningful career in the Singapoe Armed Forces.

Poon could have been jailed for up to two years and fined up to $5,000 for voluntarily causing hurt.