Train services running through East Lancs have been affected by trespassers on the railway.
Northern services running through Accrington are currently being disrupted due to the incident and could be delayed by up to 30 minutes.
Train services are unable to run between Blackburn and Hebden Bridge/Todmorden in both directions.
Emergency services are due on site shortly.
A spokesperson for Northern said: "We apologise for the delay to these services and the additional time this may add to your journey today.
"For customers on station platforms, please listen for announcements or consult customer information screens for up-to-date train running information."
The 09:19 service from Blackpool North to York was delayed for 37 minutes at Accrington, while the 10:20 Blackburn to Kirkby service was diverted via Darwen.
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