Elevated walkway in background at 1980s Potsdamer Platz seen in Wim Wenders' film “Der Himmel über Berlin”

It has to be this picture, or better scene (video clip), from Wings of Desire:

DER HIMMEL ÜBER BERLIN, brd, frankreich 1987

But then we have a certain problem:

Filming took place at actual locations in West Berlin, such as Hans Scharoun's Berlin State Library, though the Wall was recreated in studio, due to shooting the true Wall being outlawed. Some pieces of the recreation were made from inexpensive wood, with one being destroyed by rain during production.

In one scene, Damiel and Cassiel meet to share stories in their observations, with their function revealed to be one of preserving the past. Professor Alexander Graf wrote this connects them to cinema, with Wenders noting Wings of Desire itself depicts or shows places in Berlin that have since been destroyed or altered, including a bridge, Potsdamer Platz and the Wall.
_{WP: Wings of Desire}

Damiel accompanies the elderly Homer (Curt Bois) as he ambles around the empty, muddy wasteland alongside the Wall that was Potsdamer Platz, which Homer remembers from the 30s as the busy heart of the city. There's next to nothing you could recognise today, with Potsdamer Platz once again a glittering centre, dominated by the extravagant Sony Centre.

First, claiming that filming the wall was prohibited is clearly bogus, if it is meant to be applied to the Western side.
It is therefore not entirely without contradictions from the above if one finds these pictures then:

Berlin (West) M-Bahntrasse (likely real source: Brian Rose Photography, Lost Border.)

That is almost identical to the camera view from Wings of Desire. Even the text and murals on the wall are largely an identical match.

In this shot you only need to insert the actors, as even the weather seems to match (although the date seems to be a bit off for the movie, but the exact paintings are also slightly different):

Bildname: Germany-Berlin-Mitte-Mauer-1980-83, 1980. Deutschland. DDR. Berlin. Berliner Mauer. Potsdamer Platz. Magnetschwebebahn. Foto: Hellmut Münzner © Fotoarchiv Thomas Gade (Note that the photographer is certainly wrong in dating his own work to 80–83. There is a protest graffito against something: "750 Hurra", which is opposing the bruhaha of 750 Jahre Berlin. Those year-long festivities were opposed by certain groups for some time before, but took place in 1987… Equally that protext graffito is alos in the wider shot from Rose dated to 1987. Contruction of the tracks aso only started in 1983, on a different section, thus claiming "1980" for this picture is really impossible.)

If that is really just a tram bridge, then especially the smallish tracks seen in the movie still seem to indicate that the people visible on them might be illegally walking there. Or had special permissions for filming. Usually the structure was not meant for people walking at all, and there was just not much space to do so on it.

But the structure seems to have been there in 1987 when the film was shot. The M-Bahn or Magnetbahn was an elevated Maglev train line operating in Berlin, Germany from 1989 to 1991.

POTSDAMER PLATZ | BERLIN am 7.I.1987 | PETERSHAGEN | Flickr POTSDAMER PLATZ | by PETERSHAGEN POTSDAMER PLATZ | by PETERSHAGEN

This seems to be almost directly opposing shot, like capturing the place of the cinematic camera position.

_{Source: Magnet-Bahn}

This image to show the size of the tracks compared to the vehicles and that in no way were these tracks meant to be walked on.

The train line touching Potsdamer Platz on a modern map:

_{Source: Die M-Bahn – Die Berliner Einschienenbahn}

This is confirmed in an interview with the director himself:

WELT ONLINE: Woran erinnern Sie sich am liebsten?
Wenders: An die Arbeit mit dem alten Curt Bois. Wie wir da eines Sonntags morgens auf dem Potsdamer Platz gedreht haben, an der Mauer, unter der Magnetbahn, die damals da noch entlang fuhr. Kein Mensch weit und breit. Das war ja eine Stadtwüste, eine Steppe, ein Niemandsland. Die Sonne schien, es war aber trotzdem kalt. Curt war ein Witzbold.
_{Peter Zander: "Muffensausen beim 'Himmel über Berlin'", Welt, 02.05.2007.}

(How we shot it one Sunday morning on Potsdamer Platz, at the Wall, under the magnetic train that was still driving along it. Nobody far and wide. That was a city desert, a steppe, a no man's land. The sun was shining, but it was still cold.)

Interpreting this scene is then the subject of

Jonathan Bordo: "The Homer Of Potsdamerplatz—Walter Benjamin In Wim Wenders’s Sky Over Berlin/Wings Of Desire, A Critical Topography", IMAGES, Volume 2, Issue 1, pages 86 – 109, 2008.

His search for Potsdamerplatz is the theme of his principal recitation. Because of his cathexis to that place, I call him “The Homer of Potsdamerplatz” and his recitation, after Brecht, “The Song of Potsdamerplatz.” Because the recitation about that place occurs at that place, I call his recitation a “chorography.” This recitation is inaugurated by the question, “Where is Potsdamerplatz?” My essay takes up Homer’s chorography of Potsdamerplatz to show why Wim Wenders needs Walter Benjamin as his companion in order to recover the heart and soul of Berlin, a divided city in 1987, still submerged in the nightmare of its recent Nazi past.

One could easily visualize their further decay. This dreary sight led me to some thoughts which I later propounded to Hitler under the pretentious heading of “A Theory of Ruin Value.” The idea was that buildings of modern construction were poorly suited to form the “bridge of tradition” to future genera- tions which Hitler was calling for. It was hard to imagine that rusting heaps of rubble could communicate these heroic inspirations which Hitler admired in monuments of the past. My “theory” was intended to deal with this dilemma.

Der Himmel über Berlin is not about the Holocaust, even though aspects of the film explicitly address the Holocaust. The Holocaust is in the very grain of the film. The burden of acknowledgment satu- rates the very signifying apparatus itself, like the surface of a Kiefer painting, over saturated in what it shows, minimum and even evasive in what it says. Der Himmel über Berlin does not make any obvious political statements about the Holocaust and yet the film is all about it. It carries the Holocaust as involuntary memory.

This film is usually quite re-interpreted now in German media. Especially the scenes around that very place which was most heavily re-developed is a quite peculiar focus of attention. Finally a video clip filmed apparently from the tracks down onto the place of the movie scene.(clip ~one minute after the link points to.).