If you look at old maps of streetcar networks in cities (before they ripped up the tracks to replace them with cars), one thing that stands out is just how dense the networks were. For instance, here’s the old Montreal streetcar map:

Versus the modern-day Montreal metro map:

And Montreal has some of the best modern-day urbanism in North America, mind you; most cities are far worse. But it really makes you imagine what our cities could be like if we made many/most streets car-free and just had ultra-dense networks of trams again. Maybe even cargo trams to deliver goods to stores as well. Trains would be ubiquitous and ultra-convenient.