A man is due in court in Tipperary this morning in connection with possession of an imitation gun.
The incident happened on a train bound for Cork near Templemore last Friday evening.
Passengers alerted Gardai that a man was on the 7pm Dublin - Cork train with what appeared to be a gun.
Gardai searched the man and found what's believed to be an imitation gun.
A man in his 20s was arrested at the scene.
He's been charged and is due before Nenagh District Court this morning.