The rail minister has asked the industry to urgently set out a plan for resuming normal service after some trains had to be withdrawn over the weekend.
Cracks were discovered on some trains on Saturday, resulting in the Class 800 Series made by Japan’s Hitachi being pulled off lines for safety checks.
Worst-affected were Great Western Railway and London North Eastern Railway, with both operators warning passengers that they should expect disruption on Monday.
Rail minister Chris Heaton-Harris said: "Today I have directed the rail industry to urgently set out a comprehensive plan to ensure services can safely resume as soon as possible.
"I expect operators to explore all options for replacement services to help people complete their journeys, and have asked Hitachi for a safety inspection plan, as well as longer term repair strategy.
"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."
Train operators and representatives from Hitachi were invited to an urgent meeting with MPs on Sunday to discuss the problems.
Hitachi has apologised and said the trains were withdrawn as a precaution.
"We are working as quickly and safely as possible to investigate the issue across the remainder of the fleets," the company said on Twitter.
Great Western Railway has cancelled a significant number of services and said it expects disruption to extend into the week ahead.
"The problem continues to be investigated by Hitachi and once trains have been checked and cleared, we hope to be able to release them back into service as soon as possible," said GWR, which is owned by FirstGroup.
LNER promised to rebook or refund tickets for passengers who were affected.
Mr Heaton-Harris said that train operators should arrange replacement bus and coach services to help their customers.