NORTHERN has said its pre-paid ticket machines have not been affected by a glitch which mean passengers were unable to pick up their passes.
But travellers planning a trip to Bradford from stations in other parts of the country may not be so luck.
A number of operators were experiencing problems with the system, including East Midlands Trains, Greater Anglia, ScotRail, Southeastern, Southern and Stansted Express.
Photographs showing the button to collect tickets being greyed out were posted by customers on social media.
One passenger wrote on Twitter that the issue was affecting every machine at London Liverpool Street station, which is the third busiest in Britain.
He said he had to buy another ticket as "I didn't have time to wait".
A spokesman for industry body the Rail Delivery Group said: "Passengers with some train companies have this morning been experiencing problems collecting tickets from machines.
"We're sorry for the inconvenience caused and are working with the relevant supplier to fix the problem as soon as possible.
"People affected should speak to their train company or visit the ticket office."
East Midlands Trains said customers may "board their services using booking confirmation emails".
Passengers who have not pre-booked are still able to buy tickets from machines.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here