Engineering work by Network Rail on the 15th and 16th September will halt direct trains between Newcastle and Scotland. Thousands are expected to travel to Newcastle to take part in the Great North Run, many from north of the border.
Services between the two cities will have to go via Carlisle creating longer journey times. Runners and supporters help generate £22m for the regional economy each year.
Network Rail has confirmed they are talking to race organisers to address the issue.
"The works between Newcastle and Edinburgh have been planned with train operators for many months. There are four worksites over this weekend – including rockfall protection and drainage works, the importance of which has been demonstrated by the recent storms. We are also completing extensive track works in England and Scotland."
There are fears that planned rail maintenance will make it difficult for people leaving the event by train.
"Runners travelling from Scotland are still expected to travel on the Saturday as, even under the normal timetable, the earliest Sunday train would not get them to Newcastle in time for the race. There is still a train service; albeit with extended journey times. Return journeys are also extended."
More top news
Durham and Cleveland Police are joining a national crackdown on drivers using mobile phones behind the wheel.
Operation Shimmer is targeting the minority of cyclists in the city who cause a danger to themselves and others by cycling without lights.
More than 70 volunteers from six mountain rescue teams searched in subzero temperatures for 10 hours to find a missing Middlesbrough man.