British Transport Police (BTP) has warned fans travelling from Manchester to this weekend's FA Cup semi-finals at Wembley to plan their journeys home.
More than 20,000 Manchester City, Manchester United and Bolton Wanderers supporters are expected to travel.
BTP said 30 trains are scheduled to depart on Saturday for the United versus City game with just five returning in the evening.
The force has said it would be "easier" to play the ties in the North.
The Manchester United versus Manchester City semi-final kicks off at 1715 BST on 16 April, which Virgin Trains said limited the number of trains it could provide to get fans back the same day.
A Virgin Trains spokesman said that three extra trains had been laid on to deal with demand for the return journey on Saturday, which could all be delayed to accommodate extra-time.
"It's a fairly late kick-off and we are limited to how many trains we can physically get back during an evening," said the spokesman.
The Bolton Wanderers versus Stoke City tie's kick-off on 17 April is scheduled for 1500 BST, which the spokesman said would not present "so many difficulties".
BTP Supt Peter Mason said: "It's not for me to decide where fixtures are played, but for British Transport Police it would be far easier if the games were played locally.
"However, they are in Wembley and we have to manage that and we will police it accordingly.
"I hope everybody behaves themselves. As we all know, 99% of football spectators are really well behaved - it's just the small minority and they will be dealt with quite robustly."
BTP Supt Dave Roney said: "Saturday promises to be a great day for both Manchester United and Manchester City fans and our officers will be helping everyone to enjoy it, as well as ensuring everyone travels to and from the game safely.
"Throughout the day, we will have officers patrolling stations and on board trains between Manchester and London.
"We will not tolerate intimidating or anti-social behaviour from those intent on spoiling the day for others.
"Trains can become extremely busy during major sporting events such as this and we would urge fans to consider other passengers at all times.
"We're asking fans to show some consideration for others on board the train and to moderate their language and behaviour - but above all, we want them to enjoy the day."
The London Marathon, which is expected to have 32,000 participants is due to begin at 0900 BST on Sunday.
Virgin Trains has laid on an additional early morning service from Manchester Piccadilly at 0533 BST and Liverpool Lime Street at 0550 to help get runners down to London in time for the start.
Chris Gibb, Virgin Trains' chief operating officer, said: "Moving large numbers of people after any big evening sporting event poses particular challenges for the rail industry.
"The use of extra charter trains brings as much capacity as possible into use, means fans can have confidence in their travel arrangements and clubs are able to look after their supporters."