Rail staff could refuse to work on services between Balloch and Glasgow that have been blighted with unruly behaviour.
RMT regional organiser Mick Hogg issued the warning, as he outlined fears that it could only be a matter of time before a member of Scotrail staff is seriously injured or killed as a result of thugs using train services.
Earlier this year we reported how the number of crimes reported at West Dunbartonshire train stations have rocketed by almost 50 percent.