What is the relationship between the trains shown in footage from the period (black and white) and the tracking shots of the train tracks now? What is Resnais trying to accomplish by juxtaposing the past and the present in this way? The black and white footage which shows a train departing at night covered with fog and darkness. And on the other hand he juxtaposes it with the tracking shot of the train tracks now.
The black and white footage shows us that we as an audience cannot see what is really happening, nothing is clear and we as an audience cannot see the details of what is really happening. On the other hand Resnais shows us a colored picture of the railway track, showing all of the details that we as an audience are craving for. This signifies that how time can be a natural healing process for all the miseries of mankind. We as an audience know what happened in the past over these railway tracks but now all we see is the beauty of nature that surrounds it.
Also in the black and white footage the train moves in the mist of night signifying a dark and despair event, whereas in the tacking shot he shows us the same railway track in daylight to show that the today these railway tracks shares no resemblance to the atrocities that were committed through these tracks. This scene reinforces Resnais point that the same railway track that were a testimony for the worst crimes committed against humanity are now seems as innocent and beautiful as a new born baby.
The commentary by Resnais further heightens the ambivalence of the audience telling that we will never understand or know what really happened with prisoners escorted to concentration camps. I think he was trying to prove that no matter how hard we try to discover the reality of the concentration camps life we will never be able to visualize the true horrors of the atrocities that were committed.
Also through juxtaposing Resnais make the audience aware of the fact that this event is a collective trauma and therefore, it is very difficult for him to represent it to the audience. His objective is further accentuated by telling the audience in the tracking shot that we as an audience will never know what happened when the prisoners were escorted to the concentration camp.