The BBC website has an article on Darwin, the data source driving the National Rail Enquiries web and smartphone applications on location of trains, expected arrival times and so on.
The really interesting bit (to me) is that it says that third party developers will have to pay a charge for access to the data.
That surprises me. The rail industry may be privately run but it rests on franchises from government. I would have thought that made any data of this nature a public good, thus it should be available free as open data.
By comparison, the data source driving TfL's Countdown system is available free, though I think you have to register.