North East MPs are to write to Grand Central Rail bosses raising concerns at recent disruption experienced by passengers.
Hartlepool MP Mike Hill has drafted the letter due to go out later this week.
It follows a number of recent cancellations on the Sunderland to London King’s Cross line and other issues including air conditioning not working and claims of overcrowding.
Services in West Yorkshire have also been affected by electrical problems which Grand Central says it is working hard to fix.
Mr Hill raised the issues in a debate on rail services in Westminster Hall.
He called for the issues to be investigated, saying: “It is a vital service, but this year it has been struggling and not performing very well.”
Grand Central said: “Performance of our Adelante fleet has been affected by unforeseen electrical issues and air conditioning problems during the recent spell of hot weather, leading to some cancellations and alterations.
“We are working intensively with our maintenance suppliers to return to a full service as soon as possible, whilst keeping customers informed of their journey options if their train is affected.
“Grand Central increased the size of its fleet of trains from eight to ten in late 2017, and is undertaking a £10m comprehensive refurbishment programme of the entire fleet.
“Three trains have now been completed, with the programme continuing throughout 2018.”
It comes as it was announced that refurbished Northern trains and more frequent services planned to be introduced in December have been put back to 2019.
Mr Hill said: “Arriva and its subsidiary rail companies Northern Rail and Grand Central are failing the North East.
“We need new, safe rolling stock not ancient, creaking pacers. We need a rail system in the North East that functions.
“Myself and the other North East MPs are trying to put the region on the map and yet it’s difficult for us to even get a train home from London in the current situation. We need solutions now, not promises for the future.”
Northern said dropping timetable changes in December will ensure stability and reliability after the chaos earlier this year.
Northern managing director David Brown said services will begin to increase from August adding: “We remain totally focused on, and committed to, modernising the Northern network with new and refurbished trains, better stations and more services by 2020.”