Planned engineering work on the Brighton Mainline will be moved so that Brighton & Hove Albion fans can make it to Wembley on Saturday April 6.
The Seagulls will face Manchester City for the FA Cup semi-final.
The date of the works clashed with the big game, but Govia Thameslink Railway (GTR) and Network Rail agreed to reschedule the line closure.
It would have meant no trains would have been running from Brighton and Lewes to Three Bridges – the main rail route to London.
Paul Harwood, director of investment at Network Rail south east, said: “We congratulate the Seagulls on reaching the semi-finals.
“This match is incredibly important, not just to so many Brighton fans but also the wider Brighton economy, so we started planning to reschedule the work as soon as Brighton were through to the semi-finals. With the kick-off details confirmed yesterday afternoon we're now pleased to announce our decision.
“Moving the work means we can accommodate the fans, but also hold firm on our promise to complete our £67 million reliability upgrade to the Brighton main line.
“We will update passengers soon once we have confirmed a replacement date to complete the work before the summer.”
The work on Saturday, April 6 will be rescheduled to another date set to be confirmed.
However, the work planned for Sunday, April 7, will continue as advertised with a rail replacement bus service in place for passengers.
Keith Jipps, GTR infrastructure director, said: “We wish the Seagulls the best of luck. By working with Network Rail to reschedule this essential work, fans will have a much easier journey from the south coast and back."
George Hunt, the football club’s transport manager, added: “We’re delighted that we’ve been able to work with Network Rail and GTR to successfully reschedule the work to allow our fans to travel to Wembley on trains instead of replacement buses.
“We’ve worked really closely with Network Rail and GTR over the past two years and look forward to working together as we move forward.”