The Reading Viaduct, which once carried trains above Philadelphia’s urban core, has no purpose. It is abandoned. Yet its size and location in the heart of a major American city has stirred imaginings of a different kind of place, one that will be the opposite of what it is now. In fact, plans have been made, and proof of concept achieved, to transform this wild zone into a High Line–style park. But until this vision is executed, the Reading Viaduct exists as a heterotopia of deviation and illusion.

In his well known 1967 essay “Des Espace Autres” (“Of Other Spaces”), Michel Foucault invented the concept of heterotopia to describe how modern people relate to certain kinds of spaces that have ambiguous identities or functions. Oddball spaces. Ones that are “something like counter-sites, a kind of effectively enacted utopia in which the real sites, all the other real sites that can be found within the culture, are simultaneously represented, contested, and inverted.” Heterotopias are places “outside of all places.” Or as scholar Peter Johnson interprets Foucault, “sites which are embedded in aspects and stages of our lives and which somehow mirror and at the same time distort, unsettle or invert other spaces.” While the concept of heterotopia has, as Johnson says, an “elusive quality” to it that makes its use in the real world uneven and contradictory, I attempt to apply Foucault’s six principles of heterotopia to the Reading Viaduct.

Principle 1: A Heterotopia of Deviation

Heterotopias of crisis [places in primitive societies for menstruating women, adolescents, elderly, etc.] are disappearing today and are being replaced, I believe, by what we might call heterotopias of deviation: those in which individuals whose behavior is deviant in relation to the required mean or norm are placed.

It is not the case that surveillance systems train digital eyes on the space, nor that guards patrol it, nor that it is enclosed within locked doors, but it is most certainly a heterotopia of deviation. While no one is “placed” within the Viaduct’s confines—unlike those of Foucault’s examples of prison, nursing home, and psych hospital—anyone to be found herein must be said to be behaving in a deviant way, including the author of this piece in performing the role of urban explorer. But let my illustration serve as all the proof needed.

On the balmy spring day I made my first exploration, I started by using my bicycle to effect rapid movement through the streets below and around the Viaduct. I wanted to first get a feel for the size and shape of the thing. I came to a quiet street where the Viaduct passes overhead. Above me, on the tracks, a man was bending bare-assed over a hole rotted out of the surface of the railroad. He looked at me, then grimaced and completed his shit onto the street below.

Principle 2: Its Function Changes with Time

A society, as its history unfolds, can make an existing heterotopia function in a very different fashion: for each heterotopia has a precise and determined function within a society and the same heterotopia can, according to the synchrony of the culture in which it occurs, have one function or another.

Where once the railroad used the Viaduct to create a heterotopia of transit—a no place suspended in the air—now the situation is much different. It is quiet and littered; it is no longer a space to be whisked through at high speed but rather forces occupants to travel no faster than their feet can carry them; the objects and forms making up the viaduct have become monuments rather than pictures zipping across train windows. At the same time, the rails themselves have become canvasses for graffiti even as a community of plants—unchecked by human husbandry—colonizes the space. With the removal of the function of movement, the Viaduct fosters the production and sustainment of graffiti artists, vagabonds, urban planners and dreamers and schemers, and explorers. And when the Rail Park vision is achieved, the function will be radically different yet again.

Principle 3: It Juxtaposes “Several Sites that Are In Themselves Incompatible”

The heterotopia is capable of juxtaposing in a single real place several spaces, several sites that are in themselves incompatible.

Containing the former station at Spring Garden Street, which serves as a shelter for the unhoused, the Viaduct constitutes on the one hand a temporary home for those without permanent homes who seek it out, while on the other it is an experimental forest that asks Nature to demonstrate what it will do to our works that we neglect or leave behind. It is both the grove and a path through the grove yet a path that ends at the beginning; a demonstration garden. And the plant life—sumac, princess trees, high grasses—is strange-looking with its sprays of flowers and fruits.

Principle 4: It Offers a break with time

The heterotopia begins to function at full capacity when men arrive at a sort of absolute break with their traditional time.

The life of the city is above, below, and beside but wholly separate, never touching the space. Unlike museums, it does not seek to, as Foucault describes museums, gather the totality of time. Rather it is a living museum, if unintentional, of the passage of time, and how the American city surrendered its function of manufacturing. The Viaduct tells a story and, being in it, listening is easy. My eyes and ears are open.

Principle 5: It is not freely accessible

In general, the heterotypic site is not freely accessible like a public place. . . . To get in one must have a certain permission and make certain gestures.

As I’ve said, I made a circumnavigation of the Viaduct in order to locate an entrance. The viaduct is virtually inaccessible except for the one location I found: a chain link fence torn and bent into a doorway one must crouch and twist to enter. A thicket littered with garbage shows itself to be the steep bank of the former railroad. The scouting and the crouching and entering constitute the rites of entry. By performing these rites, I acknowledged that while I belonged to the public street and the city’s networks, I was also entering a place where no one is welcome, and correspondingly no one is unwelcome, either.

However, the heterotopia that is the sleeping shelter for the unhoused is another matter. By sticking to the path and staying out of the structure, I acknowledged that a separate level of permission was needed there that I did not have.

Principle 6: It mirrors the rest of space

Either their role is to create a space of illusion that exposes every real space, all the sites inside of which human life is partitioned, as still more illusory. . . . Or else, on the contrary, their role is to create a space that is other, another real space, as perfect, as meticulous, as well arranged as ours is messy, ill constructed, and jumbled.

It is the opposite of meticulous, therefore it must be a heterotopia of illusion and not of compensation. As one stands amid the disorder of the space and views the skyscrapers of Center City or the traffic flow on Spring Garden or Vine street, it constitutes a memento mori for civilization—a post-apocalyptic city within the pre-apocalyptic city. This is the way it exposes all other human sites as illusory.

However, the thinkers and fundraisers will soon transform the Viaduct into an illusion of compensation, as the section of the Rail Park that is finished—with its level pale gravel surface and minimalist furniture—demonstrates. Phase 1 is neat and sterile and separate from chaos—a portfolio of urban planning that worked in New York and which has been recreated in Philadelphia. In effect, what will be Rail Park constitutes a colonization by designers.