Underground City (Montreal Canada)  from Wikimedia Commons. I want to thank 'Laslovarga' for making this photograph available to public.

photo from Yangju city

image: Snowy Hydro

Sydney Metro West (screen grab from Transport for NSW video)

Liafjelltunnelen (image: Statens vegvesen) Norway

image Network Rail

VTA BART Phase II Board Workshop Presentation September 20, 2019