Between 1938 and 1942, Republican prisoners integrated into disciplinary units of forced labor participated in the construction and repair of the infrastructure of the line. Specifically, three Workers' Battalions (numbers 66, 69 and 163) and the Disciplinary Battalion of Working Soldiers No. 18 were assigned there. The infrastructure - esplanade, bridges and tunnels - had been completed in 1936 as far as Tortosa, but two years later the tracks only reached Pinell de Brai (Terra Alta). The Francoist offensive to reach the Mediterranean Sea in the spring of 1938 prompted the accelerated construction of the section from Alcanyís to La Ràpita. In mid-June, the line reached Pinell de Brai. During the Battle of the Ebro, which began on July 25, 1938, the communication axis, with its stations and tunnels, was the scene of heavy fighting and the tunnels were used as emergency medical centers. The fighting left the line damaged, which had to be repaired. After the end of the Civil War, work resumed with forced labour, and the section between Bot and Tortosa was inaugurated in 1942. The presence of workers imprisoned by the Franco regime destined for this line has been noted in Horta de Sant Joan , Fontcalda (Gandesa), Bot, Pinell de Brai and Xerta. Every year, the number of prisoners destined for the construction of the line exceeded a thousand men.