Why did railroad tracks become the standard division of social or economic class? Why not something that is harder to cross (and thus more likely to reinforce divisions) and is present in many towns like a creek or river?
Did the concept exist before railroad tracks were common? 'Rong region of the road to Rome?
American Heritage[sup]®[/sup] Dictionary of the English Language: Fourth Edition. Entry track, definition #8:tracks The boundary, formerly often delineated by train tracks, that separates two neighborhoods of different social class: grew up on the wrong side of the tracks.
Many cities have railroad tracks which go towards industrial areas of town to deliver and receive freight. Areas that are populated with factories and shipping ports are notorious for having a lot of poverty and crime.
I grew up in Rochester, NY. There the northeast section of the city has always been home to the many immigrant populations from the 19th century on, and the southeast section was where the rich built their mansions. The railroad tracks came into the city at grade (street level) just north of Main St., dividing the two sections of town quite distinctly. Anyone from the “wrong” side of the tracks literally had to walk across them to get to the downtown and to other, nicer parts of the city. They therefore had to dodge smoke-belching, noisy, dangerous trains to do what citizens from nicer parts of the city could do with no inconvenience.
I’m sure the concept of poorer parts of town has been around since Ur. But the train tracks seemed to typify the way 19th century American northeastern cities were put together, and it was a very powerful physically-manifesting image that everyone could understand.
From what I’ve seen, major rivers tend to create separate communities (or sometimes completely separate cities) rather than dividing a single community into separate neighborhoods. Small creeks don’t do anything - you can build as many bridges as you want, and cross them whenever you want. Railroad tracks are more of an obstacle, and far more visible than creeks.
I’ve heard that the wrong side of the tracks is the direction that the normally prevailing winds will blow the various industrial smoke, including railroad exhaust, in a town. The rich folks live in the usually soot free part, and the poor folks usually have soot all over.