I'd like to be able to see, for any station in the UK, a list of stations I can reach in a single train journey. This would be an early step in planning a trip, before looking at specific services or times.
The reason is that I often travel round the UK by a mixture of train and bike. Taking bikes on trains requires booking a bike space (usually), and things can go wrong if you miss your connection only to find there's no bike space free on the next train. So I prefer, where possible, to get one train at the start of my journey, then ride the rest of the way. Spaces can be very limited, and if one route is booked up, it's worth considering heading in a different direction.
An artificial example, where I can figure out a close-to-optimal answer easily: If I wanted to travel all the way from Bristol Parkway to Peterborough by train, I'd probably go via London. Getting the train to Paddington then riding would be about 150km. But getting the train to Derby (I thought Nottingham, but there aren't currently any direct trains) then riding would only be 100km (Birmingham New St, served by the same train as Nottingham, would be 150km again). Starting in Bristol I know the lines pretty well, so know which stations to check.
Coming home is a lot harder, e.g. Norwich to Bristol I think my best option is a train to Cambridge then ride.
So I'm looking for a way to list all the stations I can travel to without changing trains, from a particular station. If only lines/termini are listed, but I can get to a list of stations on each line within a click or two, that's also useful. Such a tool might be useful to anyone for whom changing is problematic, for example those relying on assistance (and perhaps taxis/lifts) may want to get a list of stations they can easily reach, to check accessibility and onward options.