'Ballast' was deliberately placed on rail lines causing delays to trains running between Blackpool and Preston.
British Transport Police received two reports last night of the ballast being placed on rails at Layton.
They also said pumpkins were left on the track the previous night which caused long delays for travellers.
British Transport Police Lancashire tweeted: "That caused a load of delays until we were able to establish what the train had hit in the dark."
They advised patrols have been stepped up at the location where the incidents have been happening.