Trains operated by Northern travelling through Lancaster this morning may be cancelled or delayed by up to 20mins, says the train operator.
This is due to a problem with line-side equipment at Lancaster.
Users of the service should check with the operator before they travel.
In a statement Northern said: "We are sorry for the cancellation of the service today. Please travel on the next available service.
Our Customer Promise provides for compensation to customers who are delayed by 30 minutes or longer on their journey.
"You can claim Delay Repay if one of our trains is late or cancelled and as a result you get to your destination station more than 30 minutes later than scheduled."
Normal service is expected to resume at around 8am.