A van has collided with level crossing barriers between Harrogate and York, causing the railway line between the two stations to be closed.
North Yorkshire Police and British Transport Police said they were dealing with a vehicle on the tracks at Knaresborough Station but added that nobody had been injured.
Train operators are reporting cancellations to services which could affect passengers travelling to the Great Yorkshire Show at Harrogate.
National Rail said trains running between Leeds and York via Harrogate would either be cancelled or revised to operate only between Leeds and Harrogate.
It said rail replacement services were operating and that journey times were being extended up to 30 minutes.
National Rail said the disruption was expected to last until 12:00 BST.
Early morning services from York have already been cancelled with passengers advised to travel between Leeds and York via Micklefield, train operator Northern said.
The operator said ticket holders would be allowed to travel on TransPennine Express services and CrossCountry services between Leeds and York.
In a post on social media, North Yorkshire Police said: “We’re currently dealing with a vehicle on the tracks at Knaresborough Station alongside colleagues from British Transport Police.
“Thankfully, there are no injuries. However, there is likely to be disruption for some time while the tracks are cleared.
“Please avoid the area if you can and plan your journey accordingly.”
National Rail sad network rail staff and emergency services “were on site working to deal with the incident.”
