Two cows were hit by a train after vandals stole a crossing gate in Chorley.
The gate, which stops livestock going near the line near Weaver’s Brow, was taken on Monday between 7pm and 11pm.
The train hit the two cows, killing them instantly.
British Transport Police and the RSPCA have condemned the actions of the vandals.
PC Richard King, investigating officer, said: “As a result of the vandalism, cows in a nearby farm, close to Weaver’s Brow, were able to walk straight onto the line.
“Unfortunately, an oncoming train struck two of the cows, killing them.
“This was a mindless act of vandalism that caused distress for all involved from the driver and passengers onboard the train to the rail staff who work on the track afterwards.”
RSPCA spokesperson Leanne Plumtree said: “This was an awful incident which was the result of a deliberate act by more than one person, seemingly for a kick.
“These cows suffered a needlessly terrible, traumatic death and I’d like to join British Transport Police in urging anyone with any information about what happened here to contact them urgently.”
Anyone with information is asked to contact British Transport Police on 0800 40 50 40 quoting incident number B4/NWA of 18/05/2012. Information can also be passed to independent charity Crimestoppers on 0800 555 111.