There was disruption across the rail network at the weekend after LNER issued a 'do not travel' warning following the discovery of a default during a routine maintenance check.
Hitachi-manufactured Azuma trains are being investigated for potential cracks on their chassises after the fault was discovered.
Robert Nisbet regional director at the Railway Delivery Group, said that if the trains being inspected were found to have “tiny cracks”, they would need to be treated and replacement trains brought in.
Asked if he knew how long the disruption was likely to last, he told BBC Radio 4’s Today programme: “No, I can’t put an exact time on it and that is purely because we are going through the process and taking it extremely seriously.
“If some of these trains that are being inspected for these tiny cracks are found to have them, then obviously those cracks need to be treated, in which case replacement trains may need to be brought in to fill those places on the timetable.”
Mr Nisbet said the ongoing disruption was “disappointing” as passengers had started to return to using the train network following coronavirus restrictions.
Asked how long the trains had been running with the cracks, he told BBC Radio 4’s Today programme: “These trains are relatively new in service, so this is something that the Hitachi engineers will be looking at and reporting back to the train operating companies.
“For us, as an industry, it’s disappointing and it’s dispiriting in a way to have this happen, because we were just starting to see passengers come back onto the network after a very difficult pandemic for the whole transport sector.”
Meanwhile, the Government has called on rail operators to “urgently set out a comprehensive plan” to resolve the ongoing disruption.
In a statement, rail minister Chris Heaton-Harris said: “Our focus is to ensure trains are returned to service as quickly as possible, once they are fully approved as safe. Only then can we start to rebuild a reliable and punctual timetable for passengers.
“I also want to thank passengers for their patience during what could be a significant period of prolonged disruption, likely to continue for some time.”