Actually it was the Mille Milglia in 1954:
"Herrmann had a remarkable Mille Miglia race in 1954, when the gates of a railroad crossing were lowered in the last moment before the fast train to Rome passed. Driving a very low Porsche 550 Spyder, Herrmann decided it was too late for a brake attempt anyway, knocked on the back of the helmet of his navigator Herbert Linge to make him duck, and they barely passed below the gates and before the train, to the surprise of the spectators."