All fair points. Japan does have the advantage of a higher urban population density, and steep mountain ranges mean everyone is crowded into valleys, the ideal topography for railways. One slight advantage the railway system does have in the UK is interconnection at hubs. For example if I want to go somewhere in my native city of Kobe, I often have to change from one rail line to another (there are three rail lines essentially running in parallel through Kobe), necessitating a rushed walk through crowds to the next station. In the UK you could travel from Penzance to Aberdeen without having to change stations as in Japan.
All fair points. Japan does have the advantage of a higher urban population density, and steep mountain ranges mean everyone is crowded into valleys, the ideal topography for railways. One slight advantage the railway system does have in the UK is interconnection at hubs. For example if I want to go somewhere in my native city of Kobe, I often have to change from one rail line to another (there are three rail lines essentially running in parallel through Kobe), necessitating a rushed walk through crowds to the next station. In the UK you could travel from Penzance to Aberdeen without having to change stations as in Japan.