Toilets in all 18 Network Rail-managed stations will be free to use from next year.
The organisation has announced that passengers will no longer be charged between 30p and 40p to spend a penny at many of its mainline stations, including London Euston, Leeds and Edinburgh Waverley.
Its chief executive Mark Carne said it was "wrong to penalise people when they are in discomfort".
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Which stations does Network Rail manage?
The following stations are managed by Network Rail, and so will have free-to-use toilets in 2019 (current charge in brackets):
What about other stations?
While the changes will affect some of the biggest stations in the UK, many more aren't run by Network Rail and are instead operated by separate companies, such as Greater Anglia and Northern Rail.
In some cases these companies do charge passengers to use the toilet at these stations – and that won't change as a result of today's announcement.
Virgin doesn't charge for toilet use at any of its stations on the east or west coast, and neither does Greater Anglia.
Carne said: "As a customer organisation I think it is quite wrong to penalise people when they are in discomfort.
"Our job should be to make their life easier, not more difficult. As a company we want to treat people with dignity and respect whether they work for us or use our services."