Millions of rail passengers should be given more help to claim money back when their train is delayed, the industry regulator has recommended.
The Office of Rail and Road (ORR) said that 80% of passengers do not claim compensation.
It wants clearer forms, a national publicity campaign, and better staff training, to encourage claims.
In response, the train operating companies promised to take action to improve the compensation process.
The ORR was responding to a so-called "super-complaint" by the consumer group Which?
Which? had complained in December 2015 that millions of people were being left out of pocket by the system.
Under the law, the ORR had 90 days to respond.
"We want all passengers to be able to claim the compensation they are entitled to. The information they receive needs to be better and the process must be clearer and simpler," said ORR chief executive Joanna Whittington.
Now the ORR is proposing:
Which? said the proposals were a step in the right direction.
"But this alone will not be enough to solve the problem for passengers in the long term," said Richard Lloyd, the organisation's executive director.
"The government must now ensure that the rail regulator has all the powers and duties it needs to be a consumer watchdog with real teeth."
The Rail Delivery Group, which represents operating companies, said it would be making the necessary changes.
"There is always room for improvement and we know that we can do more to give our customers an even better deal," said Paul Plummer, chief executive of the Rail Delivery Group, which represents the operators.
"We will address all of the regulator's recommendations."
It promised a new National Rail Enquiries website, with links to individual train companies and their compensation schemes.
It also said there would be better communication on social media, with barcodes on posters to enable people to claim on their smart phones.
Since last July, passengers have been entitled to compensation in cash, rather than through vouchers.
Different train operators still have different agreements on compensation, but generally passengers qualify if their train is delayed by more than 30 minutes.
So-called "Delay Repay" is gradually being introduced across the network, which means that compensation will be paid regardless of what caused the delay.
From April, all but four operators will be signed up to the scheme.
In addition some operators, including Virgin and C2C, make automatic refunds in certain circumstances.