Train services between Shotton and Llandudno were disrupted last night after thieves stole cables on the line between Talacre and Holywell signal boxes.
British Transport Police are investigating theft which caused problems to signalling equipment at around 9.30p on Wednesday evening.
Police say they have specialist cable theft officers are carrying out enquiries in the area.
Engineers worked quickly to get services back to normal last night however they remained on site working to “rectify the situation.”
Some trains were delayed by the issues last night but services have remained relatively unaffected today.
A British Transport Police spokesperson told Deeside.com
We were advised by Network Rail at 9.30pm last night (Wednesday) of a potential cable theft in the Mostyn area.
Enquiries are ongoing and we are working alongside our railway industry colleagues to establish the full circumstances.
Patrols are being conducted and specialist cable theft officers are carrying out enquiries in the area to find those responsible for the theft, which caused ongoing delays, disruption and inconvenience to passengers.
A Network Rail spokesperson said:
“Cable theft is not a victimless crime – far from it.
Train delays and cancellations directly affect people going about their daily lives, such as getting to and from work, visiting family and travelling to hospital appointments.
“We are working with Arriva Trains Wales and other partners to minimise disruption to passengers following the theft of signalling cable between Llandudno and Shotton and we would advise passengers to check before travelling.
“Trespassing on the railway is extremely dangerous and cable thieves risk serious injury or death.
We want everyone home safe every day and we continually look for ways to protect the network from thieves, working with British Transport Police to prosecute anyone caught carrying out metal thefts.”
British Transport Police are asking anyone with any information to get in touch either by texting us on 61016 or calling 0800 40 50 40, quoting reference 602 of 06/09/2017.
Information can also be given to Crimestoppers anonymously on 0800 555 111.