The communication cord is there for a reason, and if you are already stopped its a very handy gadet
The guard has a radio
Newer trains have a intercom to the driver and CCTV
Best practice is to corner the individual, there was a case in the UK recently where a passenger was stabbed and the train manager managed to lock the guilty party in a coach by himself, he did escape by breaking a window
Dublin Waterford has a bad history on troublesome passengers drink was banned on some trains and security brought in
|