A picture of cars on a train wagon waiting to cross the Alps through a tunnel in Switzerland.
Although I don't know the exact location of this picture - the slide mount just says, 'Tunnel through the Alps', I think it may be the Lotschberg Tunnel. Some other pictures on Wikipedia suggest this, but it's difficult to be sure from just those pictures so any confirmation or correction would be welcome.
In the picture, we can see the signal lights at red and cars on board train wagons, waiting for the light to change and the journey to start. It's just possible to see, right at the front of the line of cars, the engine which will pull the load through the mountains and directly above it a clock is indicating that the picture was taken at midday. Right on the very extreme left of the picture is the face of a woman caught by the camera which suggests the photographer was waiting on a platform of people, possibly for a train coming through the tunnel.
The exact date is unknown but is part of a whole series of pictures dating from the early 1960s so I've no reason to think this is anything other than about that date.