Trench railway

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.

France had developed portable Decauville railways for agricultural areas, small-scale mining and temporary construction projects.

British War Department Light Railways and the United States Army Transportation Corps used the French 600 mm narrow gauge system.

Unskilled labourers and soldiers could quickly assemble prefabricated 5-meter (16 ft 5 in) sections of track weighing about 100 kilograms (220 lb) along roads or over smooth terrain.

Small locomotives pulled short trains of 10-tonne (9.8-long-ton; 11-short-ton) capacity cars through areas of minimum clearance and small-radius curves.

[2] Steam locomotives typically carried a short length of flexible pipe (called a water-lifter) to refill water tanks from flooded shell holes.

Prior to outbreak of war 150 km (93 mi) of military 600 mm (1 ft 11+5⁄8 in) track were stockpiled at Toul, along with 20 locomotives and 150 wagons.

The "Système Péchot" as it is named in French became the dominant system for trench railways with an estimated 7,500 km (4,700 mi) of track built by the 5th engineer regiment.

One hundred-eighty-two Zwillinge were manufactured from 1890 to 1903, and shortcomings were evaluated in German South West Africa and China's Boxer Rebellion.

Deutz AG produced two hundred 4-wheel internal combustion locomotives with an evaporative cooling water jacket surrounding the single cylinder oil engine.

Much of the trench railway equipment remaining in Belgium at the end of hostilities was shipped to the Belgian Congo to build the Vicicongo line.

One hundred 15-tonne (33,000 lb) 2-6-2T of the American standard military design were later purchased from Alco's Cooke Locomotive Works for British use.

Britain pioneered the use of petrol-powered, 4-wheel synchromesh mechanical drive locomotives (known as tractors) for daylight use within visual range of the front.

In 1916 the War Office required "Petrol Trench Tractors" of 600-mm gauge that were capable of drawing 10 to 15 tons at 5 mi (8.0 km) per hour.