UTL is about exploring past, present and future urban technologies in science and fiction, etc...
https://en.wikipedia.org/wiki/Light_rail#Lower_capacity
https://www.railwaygazette.com/knowledge-hub/urban-railway-operators/light-rail-/-tramway
https://en.wikipedia.org/wiki/SEPTA_subway%E2%80%93surface_trolley_lines
https://en.wikipedia.org/wiki/Pittsburgh_Light_Rail