Hi,
I highly recommend this film. Others here have already given praise to the quality of acting and directing of the film, so I won't bother with that, other than I agree completely.
There are some points not covered so far in the history of the film though. It was mentioned that the bombing runs were by the French Air Force...true. To the "special effects", there really aren't any. The French railroads had all recently converted, or in the process of converting to diesel by the time of this picture, so they had all these now obsolete engines and rolling stock from the war years laying around. If you're wondering why and how these locomotives were crashed like this, the crashes were real. All this equipment was destined for the scrap yard. When the arrangements for this film were being made, many seemed that being destroyed at full steam and full throttle was a FAR more fitting end to the life of a locomotive than in a scrap yard and the cutting torch, so that's exactly what they did. If memory serves, the only true fabrication was the German armored locomotive towards the beginning of the film (destroyed in the air raid). It had to be build over a French locomotive (..plywood and canvas, I think) then painted. The end result is an accurate depiction of equipment the Germans used, but none of that survived the war.