UTL is about exploring past, present and future urban technologies in science and fiction, etc...
https://en.wikipedia.org/wiki/7_(New_York_City_Subway_service)#Rolling_stock , https://en.wikipedia.org/wiki/New_York_City_Subway_rolling_stock
https://en.wikipedia.org/wiki/Montreal_Metro#Rolling_stock
https://en.wikipedia.org/wiki/Chicago_%22L%22#Rolling_stock