A brawl at Kings Langley railway station delayed train passengers until the early hours of Sunday morning.
British Transport Police officers were called to the scene just before 1am, when three men aged 54, 24 and 22 were arrested on suspicion of affray and later bailed pending police enquiries. A 19-year-old man was also cautioned for being drunk and disorderly.
A London Midland train leaving Euston just after midnight was held at the station for around 45 minutes due to the incident.