World's oldest metro systems - Railway Technology
End London-centric approach and invest £140bn in 11 underground systems, Scape say | Infrastructure Intelligence
Why is London the only city with a subway system in the UK? - Quora
What the Subway Is Like in 16 Different Cities.
MTR - Wikipedia
London Underground: The UK cities with an underground Tube system you might not know about - MyLondon
The World's Oldest Metro Systems - WorldAtlas
A tale of two metros: how the London tube beat the New York subway | Underground cities | The Guardian
London Underground | subway, London, England, United Kingdom | Britannica
London Underground: The UK cities with an underground Tube system you might not know about - MyLondon
Why do so few cities in the UK have metro systems? - Quora
How many cities have underground in UK? - Quora
Longest Metro And Subway Rail Systems In The World - WorldAtlas
Railway revolution as 34 new train stations could open across UK - see full list - Mirror Online
Revealed: London's secret underground railway system - CNN Style
This is why Reading and four other Berkshire towns are on the London tube map - Berkshire Live
Rail transport in Great Britain - Wikipedia
The power of urban rail - Arup
List of metro systems - Wikipedia
Britain's Other Underground Train, Tube, Metro Rail Systems, and Networks - Anglotopia.net
Britain's Other Underground Train, Tube, Metro Rail Systems, and Networks - Anglotopia.net
Going underground: the cheapest, deepest, oldest subway systems in the world – but which is home to its own mosquito? | South China Morning Post
Why do so few cities in the UK have metro systems? - Quora
London Underground: The UK cities with an underground Tube system you might not know about - MyLondon
