Learning that a Prussian troop train was to pass through Lanois (on the line between Reims and Mons) on October 26, 1870, they resolved to effect its destruction. How they operated is told by Lieutenant Fraser, R. E.,[25] who arrived on the spot shortly afterwards, and heard the story from some of the men engaged on the work. Any obstruction placed on the line would have been seen. Hence a different course had to be adopted. Selecting a spot where the line ran along a 12-ft. high embankment, to which a well-wooded slope came down on one side, the _franc tireurs_ took up a pair of rails, removed the sleepers, cut a deep trench across the line, laid some pieces of iron at the bottom of the trench, placed on the iron a box containing thirty kilos (2 qrs. 10 lbs.) of powder, and fixed into the lid of the box a French field shell in such a way that, when the rail was replaced over the box, the head of the fuse would be just below the lower flange of the rail. In restoring the line again in order that there should be nothing to attract attention, the _franc tireurs_ omitted one sleeper so that the weight of the locomotive should in passing press the rail down on to the head of the fuse. The party--some seventy-five strong--then withdrew to the shelter of the woods to await developments. In due time the train of forty coaches approached at the ordinary speed, the driver not suspecting any danger. When the engine reached the spot where the "torpedo" had been placed, an explosion occurred which tore up a mass of earth, rails and sleepers, threw the engine and several carriages down the embankment, and wrecked the train. Those of the Prussian troops who got clear from the wreckage were shot down by the _franc tireurs_ under the protection of their cover. The number of the enemy thus disposed of was said to be about 400. Altogether the French, in their efforts to impede the rail movements of the invader, destroyed many miles of line, together with no fewer than seventy-eight large bridges and tunnels, apart from minor interruptions. The repairs and reconstruction thus rendered necessary threw a great amount of labour on the Prussian Railway Troops, and much trouble arose from time to time on account, not only of the inadequate supply of materials even for temporary constructions, but, also, by reason of the shortcomings of the workers themselves. The sections of Railway Troops had been so recently formed that the men were still without adequate training. In 1870-71, as in 1866, military members and civilian members of the Construction Corps were alike unfamiliar with the special class of work called for in the repair or the rebuilding of railways under the emergency conditions of actual warfare. This instruction had, in fact, to be completed at the theatre of war at a time when the Corps should have been prepared to show the greatest efficiency.