CrossCountry has cancelled almost all of its UK services after a power cut at its control centre in Birmingham on Saturday.
The outage has rendered many of the systems used to manage the railway unavailable, the operator stated.
Cancellations are affecting most routes, from Glasgow to Penzance and Leeds to Manchester, until further notice due to "significant and unforeseen disruption".
Transport Secretary Heidi Alexander said she was "concerned to hear about a power outage" and had asked publicly owned operators to provide "extra services where possible".
"We've also sent Network Rail power teams who are onsite and working to restore power and systems as soon as possible," she added.
Passengers have expressed their frustration on social media, describing the situation as the "worst case scenario" for a weekend, with some opting for coaches to continue their journeys with other operators.
Major routes affected include those between Manchester and Birmingham (passing through Stoke-on-Trent, Coventry, and Wolverhampton), Leeds and York, Cheltenham and Cardiff, and Glasgow and Edinburgh.
CrossCountry confirmed that tickets for Sunday would remain valid until Wednesday.
When asked on X if the situation would be resolved by Monday, the operator responded: "We would hope so, but at the moment we have no further updates."
Fans travelling to football fixtures have been warned that services to and from Manchester, Liverpool, and Newcastle might be "extremely busy".
Reese Proctor described the cancellations as "frustrating and unacceptable" as he attempted to reach Manchester's Etihad Stadium for a 14:00 BST kick-off against Bournemouth. He had planned to take a train from Reading to Manchester but ended up driving over 100 miles to a friend's house in Leicester before continuing to the stadium.
The 22-year-old told BBC Newsbeat the drive added an extra two hours to his journey, leaving him "fuming".
"If I couldn't drive, or have [my friend] to drive... I wouldn't have been able to go to the match. That would have been a waste of a match ticket," he said.
Another passenger posted on X: "A massive thank you to Cross Country Trains for cancelling my train this morning to Birmingham. You are truly not fit for service. You have also cancelled my train coming back but that is immaterial. Useless. Utterly useless."
Services to Plymouth and Penzance are also disrupted, with customers using Great Western Railway operators as a replacement.
"We are working closely with relevant partners and will provide further updates as soon as possible," a CrossCountry spokesperson stated.
Chiltern Railways announced it had added services between Birmingham Moor Street and Oxford to help alleviate the disruption, accepting "all CrossCountry tickets via any reasonable route".
London North Eastern Railway also confirmed it would accept CrossCountry tickets "to help get affected customers to their destination".
At New Street station, platform barriers were open, and regular announcements informed passengers about the disruption. Digital boards displayed a Special Notice regarding the CrossCountry service cancellations.
While CrossCountry typically serves over 100 stations, the only route expected to have a "near-normal" service was between Peterborough, Cambridge, and Stansted Airport.
The company apologised to affected passengers and confirmed that tickets were being accepted by other operators.
Customers are eligible for Delay Repay compensation if their train is delayed by 30 minutes or more. Those who choose not to travel can claim a refund for their journey.
National Rail advised affected customers they could use London Underground services at no extra cost, as well as West Midlands Metro services between Wolverhampton and Birmingham New Street.
Train tickets purchased for CrossCountry services on Sunday will be valid for travel until Wednesday.
The organisation cautioned football fans: "You may need to stand for part or all of your journey. If you require any assistance, please speak with a member of staff."
