Trench railways represented military adaptation of early 20th-century railway technology to the problem of keeping soldiers supplied during the static trench warfare phase of World War I. The large concentrations of soldiers and artillery at the front lines required delivery of enormous quantities of food, ammunition and fortification construction materials where transport facilities had been destroyed. Reconstruction of conventional roads (at that time rarely surfaced) and railways was too slow, and fixed facilities were attractive targets for enemy artillery. Trench railways linked the front with standard gauge railway facilities beyond the range of enemy artillery. Empty cars often carried litters returning wounded from the front. Overview France had developed portable Decauville railways for agricultural areas, small-scale mining and temporary construction projects. France had standardized narrow gauge Decauville military equipment and Germany adopted similar feldbahn of the same gauge. British War Department Light Railways and the United States Army Transportation Corps used the French narrow gauge system. Russia used Decauville narrow gauge and narrow gauge systems. Unskilled labourers and soldiers could quickly assemble prefabricated sections of track weighing about along roads or over smooth terrain. The track distributed heavy loads to minimize development of muddy ruts through unpaved surfaces. Small locomotives pulled short trains of capacity cars through areas of minimum clearance and small-radius curves. Derailments were common, but the light rolling stock was relatively easy to rerail. Steam locomotives typically carried a short length of flexible pipe (called a water-lifter) to refill water tanks from flooded shell holes. Steam locomotives produced smoke that revealed their location to enemy artillery and aircraft. They required fog or darkness to operate within visual range of the front. Daylight transport usually required animal power until internal combustion locomotives were developed. Large quantities of hay and grain were carried to the front as horses in warfare remained essential to logistics. Fodder for horses constituted the single biggest commodity exported from Britain to France during the war. French equipment French equipment was largely designed on the initiative of Artillery Captain Prosper Péchot beginning in 1888. The Fairlie articulated 0-4-4-0T Péchot-Bourdon locomotive was named for him and engineer Bourdon of the 5th engineer regiment (5e régiment du génie) in Toul. Prior to outbreak of war of military track were stockpiled at Toul, along with 20 locomotives and 150 wagons. The French military had 62 Péchot-Bourdon type built between 1888 and 1914. Baldwin Locomotive Works built 280 more