“Like many metaphors, “the other side of the tracks” was originally a literal epithet. Blacks were often historically restricted to neighborhoods separated from whites by railroads, turning the tracks into iron barriers of race and class.
In many cities, these dividing lines persist to this day — a reflection of decades of discriminatory policies and racism, but also of the power of infrastructure itself to segregate.
Look at racial maps of many American cities, and stark boundaries between neighboring black and white communities frequently denote an impassable railroad or highway, or a historically uncrossable avenue. Infrastructure has long played this role: reinforcing unspoken divides, walling off communities, containing their expansion, physically isolating them from schools or parks or neighbors nearby.”