Hove MP Peter Kyle is to ask Network Rail bosses to postpone a shutdown between Brighton and Three Bridges on the day when thousands of football fans will be heading to Wembley.
Brighton and Hove Albion take on Premier League champions Manchester City either on Saturday 6 April or Sunday 7 April in the semi-finals of the FA Cup.
The fixture takes place on a weekend when Network Rail plans to close the line from Three Bridges to Brighton – affecting passengers travelling on east and west coastway services too.
Fans choosing to travel by public transport will face the challenge of crowding on to rail replacement buses.
Coach operator National Express plans to lay on extra coaches on the day of the match.
It is the official travel partner for Wembley Stadium and will be able to take fans directly to the stadium.
Although Mr Kyle, the Labour MP for Hove, is not known as a football fan, he has spent a great deal of time pressing rail bosses for a better service.
In the FA Cup, a win for Brighton would earn the club £1.8 million while the losers will pick up £900,000.
If the Seagulls win, they will play in the FA Cup Final on Saturday 18 May.