The armistice concluded on November 11, 1918 obliges German Reich to give to France, within 30 day, the railway lines exploited by network EL, with their personnel and the hardware.
June 19, 1919, a decree of the General Police chief of the Republic creates the Railway administration of Alsace and Lorraine (initial Al). The decree of November 30, 1920 attaches this entity to the Public Ministry of Labour.
The evolution of network Al is often the reflection of the international life and depends in major part of the economic and political relations existing between France and Germany. Because of its geographical situation, the network is particularly sensitive to the external influences likely to modify the international trade flows. Strasbourg remains the heart of the economy of old Reichsland but commercial flows are reversed completely. If in 1913, the Alsace-Moselle carried out with France a traffic of 1,8 million T and with Germany of 17,8 million T, these tonnages are respectively 14,6 and 7,6 million T in 1929. The supply of the three departments, the Rhenish countries and Palatinat occupied by France as well as transport towards France of the Lorraine iron ore and the coals of the Saar and the Ruhr require a general recasting of the railway system.
At the nationalization in 1937, Al remains the only French network in good financial health. Stock list at December 31, 1937 breaks up into: 1332 engines, 34 rail-cars, 3390 cars, 1065 vans, 83 coach-stations, 45967 coaches, for a population of 39039 railwaymen. The total length of the exploited lines and 2320 km.