Union bosses have warned removing guards from trains will lead to a rise in crime.
Guards on Northern staged a third one-day walkout yesterday, causing problems for travellers between Blackpool and Preston.
Less than half of the normal number of services operated with Northern operating a limited timetable between Blackpool North and Manchester Airport.
Some trains also ran between the resort and Burnley.
RMT members were on strike over plans to introduce driver only operations on 50 per cent of all Northern services.
The union has in the past focused on safety concerns in its opposition to the proposals.
Now General Secretary Mick Cash has claimed passengers could face higher levels of crime on the railway.
He said: “Removing staff from trains, which travel through over 300 unstaffed stations, is a toxic combination that will increase anti-social behaviour unleashing a surge in crime which will see Northern rail becoming a muggers’ paradise.”