Rail
There is a well established intercity and local train network covering the major towns and cities, albeit that there are several operators and fare pricing structures which can make the system appear overly complicated.
Whilst there are exceptions in some rural areas, tickets have to be purchased prior to boarding the train tickets and can be purchased right until departure as they are not linked to a specific seat on the train. However, significant savings can be made for purchasing tickets in advance of travel for most longer journeys with a guaranteed seat.
Network Rail (www.networkrail.co.uk) provide a helpful website which contains a journey planner and a comprehensive guide to the rail network.
Tickets can be purchased from vast majority of stations, and online from the train operating companies. XXXXX is recommended
Unfortunately, there is currently no standardized smart card or digital ticket option yet and you often have to have the card or smartphone app for the relevant train operator.
On longer distance trains there is first class accommodation offered in addition to standard class, however this considerably varies between operators and can be considerably more expensive.