Police are searching for a group of boys after concrete placed onto a railway line was struck by a train.
British Transport Police (BTP) has released images of three boys after concrete debris was placed on the line near Ridley Lane in Croston, rural Chorley.
The incident happened at 5.20pm on Wednesday, August 14.
"It is the sixth time concrete debris has been placed on the tracks in the area," said a spokesman for BTP.
"Placing items on the tracks is extremely hazardous.
"Those involved are endangering their lives and could possibly cause severe damage to trains."
A train struck the conrete debris on August 14.
Thankfully, there was no major incident.
Officers believe those pictured may have information that can help their investigation.
Anyone who knows them is asked to contact BTP by texting 61016 or by calling 0800 40 50 40 and quoting reference number 440 of 14/08/19.
Alternatively, call Crimestoppers anonymously on 0800 555 111.