Rail passengers issued with a penalty fare after making an "honest mistake" will have greater protection under rules which come into force on Friday.
Anyone with a genuine reason for not having a valid ticket will be able to challenge a penalty through an independent committee unconnected to train companies.
Once an appeal is received the clock will stop on the 21-day deadline for payment until the outcome of the dispute is decided.
The new system will give greater consideration to the circumstances of how and why penalties are issued in a bid to ensure people are treated fairly, according to the Department for Transport.
Rail minister Jo Johnson said: "Rail users should make every effort to get the right ticket for their journey, but if you make an honest mistake you should feel confident that the appeals system will recognise this and treat you fairly.
"We are simplifying the rules around penalty fares and introducing an independent appeals process to help those who make a genuine error when using the railway."
Penalty fares can be issued when someone travels without a ticket, is unable to produce a railcard on a discounted ticket, travels in first class with a standard ticket or stays on a train beyond the destination they paid for.
Passengers receive a charge of either £20 or twice the cost of a full single fare, whichever is greater. That can lead to penalties reaching hundreds of pounds for long distance trips.
Jacqueline Starr, managing director of customer experience at the Rail Delivery Group, representing train companies, said: "Customers sometimes make genuine mistakes and the changes to the penalty fares system, which is meant to deter fare dodgers, will help those who feel they have been mistreated and ensure there is enough time to deal with their appeal.
"Fare dodgers deprive the railway of about £200 million every year, money which would otherwise be invested to improve Britain's railway for customers, communities and the economy."
Alex Hayman, managing director of public markets at consumer group Which?, said: "Some people will occasionally make a genuine mistake when travelling by train - that could include a commuter accidentally leaving their season ticket at home, or a passenger choosing the wrong option because of a complex and confusing ticketing system.
"It's encouraging that these passengers will now have an independent body to turn to if they decide to appeal their penalty, so that they can be confident that the issue will be resolved fairly."