Given my familiarity with Grand Central Terminal, it came as a surprise to learn of a hidden world lying directly beneath the public spaces of the station. This subterranean world is revealed by Accra Shepp in "Tunnel Visions," an exhibition of eighteen large-scale black-and-white photographs. The under-ground station represented in Shepp's photographs is as private as the station above is public, as dark as its counterpart is light, and as devoid of people as the upstairs is full. This is a world filled with utilitarian structures - pipes, ducts, machinery, generators, and gauges. This is the heart of Grand Central Terminal, the infrastructure that provides power for the trains and heat and light for the huge station above. This is the command post, where dispatchers route incoming and departing trains.

Shepp photographed the nether regions of Grand Central Terminal from April through August 1993, after receiving an invitation to participate in a project about 42nd Street. Deliberately avoiding the Times Square area, and looking for an underexposed aspect of the all-too-familiar midtown district, he settled on Grand Central Terminal as the subject of his investigation. His view of the station differed markedly from that of guide-books, which inevitably highlight the terminal's distinctive architectural character. To Shepp, the terminal above ground is only part of a much larger and more integrated vision:

The fragmentary glimpses offered by Shepp's photographs reveal an eerie and surreal world. This world possesses a stark industrial beauty. Humans are invisible, although traces of their presence are everywhere evident. Control towers A and B occupy this part of the terminal, along with a steam plant, the source of steam for the entire terminal and, at one time, for all of midtown. Electricity to power the tracks and to light the tunnels is also generated here. Steam Leak at 48th Street shows a common underground occurrence, which apparently can go undetected for weeks. A spotlit jet of steam in the shallow foreground space is juxtaposed with the deep space of a tunnel, which vanishes into the darkness of the picture plane. This vast underground space is a counterpart to the main concourse above ground, its sense of the sublime reminiscent of Piranesi's prison series without the tiny figures.

Two other untitled architectural views show the incongruity of functional structures built in a prefabricated vernacular style, a set amid decidedly undomestic surroundings of tracks and tunnels. In one, only graffiti and the scrawled numeral 13 give testimony of visitors; in the other, a spectral figure can be discerned on the stairs. Machines, pipes, and ducts appear more prominently in two other untitled works. Five Views of Steam Plant is made up of separate prints, each with a different mechanical element - a boiler, a turbine, a pump, and a water heater - at the center of its composition, framed by at angled network of ducts and pipes of all shapes and sizes. Even without knowing the identity of the objects, we can see that they all serve important functions. The screenlike mechanism in Tower A Switching Mechanism creates an overall planar composition of geometric precision and beauty.

Other photographs focus on the foundations of Grand Central Terminal, underscoring the layers on which the structure is built. for example, Ten Views of the Madison Avenue Yard captures a variety of piers that support the ceiling. The piers - clearly man-made are set against the rock walls out of which the station was excavated. Detritus left behind by a century of track workers is also visible. One photograph in this group shows an incongruous meeting of a smooth, man-made niche, rough bedrock, functional tubing, and a weirdly truncated taped pipe. Another, one of two photographs in this series which show areas accessible to the public, presents the lower concourse of Grand Central Terminal. Originally, Shepp had conceived his project as a series that included views from below, at, and above grade.

The photographs in "Tunnel Visions" utilize lighting found on location. The exposure times for each composition vary, ranging anywhere from fifteen seconds for an individual photograph to a total of half an hour for a large photographic composite. Sometimes, however, the lack of sufficient light forced Shepp to abandon a location.

With the exception of Five Views of Steam Plant, the photographs are composites - the overall image is made up of two, three, or four individual parts, lined up to coalesce into a single whole. Shepp compares the photographs composed of horizontally arranged units to books and those of vertically stacked units to bricks. Visible black borders delineate each section. Shepp regards this "frame" as an important architectural element, and he decides how thick it should be for each photograph. The shape of the negative holder is also visible on the printed photos, reinforcing the constructed quality of each image. Shepp also decides where to place the breaks in the overall image. He finds what he calls a "metastable" position, the point at which each individual section can stand on its own as an independent image, as well as forma part of a larger contiguous image. The diptych, triptych, and polyptych formats of the works, coupled with their large size, underscore the iconic quality of the images.

The composite structure destroys the sense of illusion we might be tempted to look for in the photographs. The black lines framing the individual units serve as reminders that photographs are analogues to visual reality, not transparent windows onto the world. Photographs can present us with views that are different from what our eyes tell us. For example, the untitled shot of a pump house gives us the floor and ceiling at the same time, something we are incapable of seeing without tilting our heads. Shepp observes:

Shepp's photographs of Grand Central Terminal continue his earlier investigations of industrial sites and functional architecture. After graduating from Princeton University in 1984, he moved back to New York City, where he had grown up, and enrolled at the Institute of Fine Arts to study art history and conservation. A fellowship allowed him to spend two months in Italy. There he photographed ancient architecture, which he describes as "muscular," appreciating the ways in which the buildings' functions are expressed. At the same time, Shepp began to shoot well-known public spaces in the city, such as Coney Island the Brooklyn Bridge, and industrial areas of New Jersey. Two untitled works of 1989, one a view under the Brooklyn Bridge, and the other an image of a trestle bridge near New Jersey, are irregularly shaped and composed of several units that construct a visual analogue to the structure pictured in the photographs. From 1989 to 1991 he photographed a series industrial sites in Cleveland, including Blast Furnace 5 and 6 and Oxygen Lance I, that utilize the rectangular composite form he later employed for the works in "Tunnel Visions."

Initially, the photographs in "Tunnel Visions" appear to be linked to the tradition of industrial photography that flourished, in the United States and Europe in the 1920s, a decade sometimes known as the Machine Age. On this side of the Atlantic, Charles Sheeler, Paul Strand, Edward Weston, and margaret Bourke-White paid tribute to the rise of technology and the conviction that it would improve the world. Sheeler's 1927 advertising campaign for the Ford River rouge plant near Detroit is a classic example of this utopian exaltation of the machine and technology. these photographs emphasize the sleek, clean lines and abstract geometric patterns formed by the factories and machinery, an aesthetic that affirms the rational logic underlying technological advances. The aesthetic in Shepp's photographs is much grittier, and the machines much older. Five Views of Steam Plant show aging technology, machinery that has been spent a long and productive career, pipes and ducts that swollen and frayed with use. It is not difficult to imagine asbestos lurking beneath the numerous taped pipes. In this subterranean world, there is a sense of the outmoded, the past. Shepp's awareness of history is consisten with his archaelogical exploration of Grand Central in which the station becomes another chapter in an ongoing and unfolding present and future.