English: The image shows the original Strahlloch Bridge (or Viaduct) and the directly adjoining Strahlloch Tunnel at km 64.2 of the Gotthardbahn. Strahlloch Bridge and Tunnel are part of the double loop in Wassen on the northern access ramp to the Gotthard Rail Tunnel. Going south on the Gotthardbahn and up the northern ramp, having passed Wassen Station you pass from the Strahlloch Tunnel onto the Strahlloch Bridge before entering the second turn tunnel of the double loop the Leggistein Turn Tunnel. With the Leggistein Tunnel in his back to the right the photographer was looking in the opposite direction across the Strahlloch Bridge onto the northern portal of the Strahlloch Tunnel.

The picture was taken before 1878 with commercial operation of this central part of the Gotthardbahn only starting in June of 1882 and the ramps and the Gotthardtunnel still under construction. The bridge shows the single beam truss construction that was typical for the majority of the original bridges on this line, and which later had to be fortified with supporting fishbellies or arches with increasing traffic loads until they eventually had to be replaced with reinforced concrete or other bridges.

The original is a photograph by Adolphe Braun published in a probably small edition book "Photographische Ansichten der Gotthardbahn" (58 photographs (28x23 cm2) mounted on each single page plus one two-page panorama), published around 1875 or shortly thereafter. The exact date of publication is not clear. The original in the book was photographed at an angle and the resulting image was clipped to show central detail and to reestablish a rectangular frame. The resulting image is somewhat distorted with respect to the original photograph by Adolphe Braun and very much reduced in resolution. The German caption of the photo in the book reads "Strahllochbrücke" (Strahlloch Bridge).