English: The image shows a pneumatic locomotive used during the construction of the Gotthard Rail Tunnel behind an archway or short tunnel of just a few meters. The original caption of the image translates to "Tunnel Entrance in Airolo", which probably indicates the approximate location of the shown arch, which is not the southern portal to the Gotthard Rail Tunnel itself.

The shown pneumatic locomotive stored energy in the form of compressed air in the large pressure container up front. The released expanding air was used to operate the motor of the locomotive. Steam driven compressors were readily available at the time of the construction (1872-1880) and for example in use to drive pneumatic drills. Most probably these compressors were also used to load the pressure containers outside the tunnel. (The first DC motors were just being developed and the AC motor was patented by Tesla only in 1888.) In contrast to steam engines the pneumatic engines did not require additional ventilation of the tunnel during its construction. Even using pneumatic technology the tunnels were poorly ventilated adding to the poor work conditions.

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 "Tunneleingang in Airolo" (literally: Tunnel entrance in Airolo).