The train car shows up twice in Silent, at the very end of the story.
It had been a dining car before it was employed as Marshal Ferdinand Foch’s office on wheels for the last few months of World War One. On November 11th, 1918 it was parked in the forest of Compiègne, north of Paris. Here, early, on a cold, drizzly morning, the Germans arrived and signed an armistice with the Allied Forces, ending the war.
After a few years on display in Paris the train car was taken back to Compiègne and placed in a little museum commemorating the end of the war.
Cut to: June 22nd, 1940. After the Germans crushed the French Army in the first months of World War Two, Adolf Hitler forced the French to sign their surrender in the very same train car. Knocking the wall of the museum down he had the car moved to the exact spot it had been on the morning of November 11th, 1918.
Afterwards, the car was taken to Berlin and displayed for a time, until it was relocated to the town of Crawinkel Germany. By 1945, with the war going badly for Germany and the American forces approaching the town, the SS set the car on fire, destroying it.
In 1950, another car, built at the same time as the original in 1913, was dedicated and placed in the rebuilt museum in Compiègne. You can see it there today.