Where can one book tickets for train journeys across the UK?

* Trainline: Popular, user-friendly website and app for train travel in the UK.

* National Rail: Official website for train travel in the UK, also has a mobile app.

* TrainPal: A mobile app that allows users to compare prices and book train tickets.

* Redspottedhanky: Offers discount train tickets and can be used for advance bookings as well.

* RailEasy: A website that provides information on train schedules and allows users to book tickets.