Rail passengers were stunned to see armed police at Mirfield station.
The officers swooped on the station car park off Station Road at the height of rush-hour yesterday after reports a man had been seen with a shotgun.
One man was later arrested and remains in custody, although no gun has been found.
Det Insp George Bardell, of Huddersfield CID, said inquiries were continuing.
The drama happened shortly after 6pm when police received a 999 call from a driver who had been at the station.
Det Insp Bardell said: “The caller told police he had seen what appeared to be an altercation between three men outside the railway station.
“One of the men produced what appeared to be a shotgun.
“Armed officers were sent to the scene and no doubt many train passengers would have had a bit of a shock to see them around the station.
“A car which had been identified to police was stopped close to the scene and a 27-year-old man was arrested on suspicion of possession of a firearm.
“A search was made but no gun was found.
“However the man remains in custody having also been arrested for possession of an offensive weapon and possession with intent to supply cannabis.
“Our inquiries are continuing.”