Saint-Michel-de-Maurienne derailment

The Saint-Michel-de-Maurienne derailment of December 12, 1917 was a railway accident involving a troop train carrying at least 1,000 French soldiers on their way home for leave from the Italian front in World War I. A derailment as the train descended the Maurienne valley rail line caused a catastrophic crash and subsequent fire in which approximately 700 died. France's deadliest rail accident, it occurred on the Culoz–Modane railway line, part of the Fréjus Railway.

Due to a shortage of locomotives in the area, the local commanding officer for rail traffic chose to couple two trains with a combined 19 coaches to a single 4-6-0 engine. Of those coaches, only the first three had air brakes, the remaining coaches had only hand brakes or no brakes at all. The train driver initially refused to drive such an overloaded train, which was now four times the safety limit for the engine, but was threatened at gunpoint by a French officer and forced to proceed.

On leaving Modane, the train descended into a valley. The driver applied the brakes to no effect, owing to the heavy load, and quickly lost control of the train. After continuing at dangerous and uncontrolled speeds of up to 135 kilometres per hour (84 mph) for nearly 6.5 kilometres (4.0 mi), the first coach derailed at Saint-Michel-de-Maurienne, causing a pile-up and resultant fire. Because of the fire and impact, only 425 of the 700 troops killed could be identified.

On the night of December 12/13, 1917, military train number 612 was returning from Italy filled with French soldiers who had spent a month helping Italian troops in the aftermath of the Battle of Caporetto. After passing through the Mont Cenis Tunnel the train reached Modane station, where two additional cars were coupled to the train before the journey onward to Chambéry. From there they were to disperse to join their families throughout France for 15 days of leave covering the year-end holidays. The train stopped at Modane for 1 hour to allow other trains to pass. Most of the officers left the train during this stop, to take the Modane-Paris express.

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