Throughout the First Republic, workers on the Central do Brasil Railroad (EFCB) constituted one of the first categories to have their rights guaranteed by the State – which occurred through the creation of Retirement and Pension Funds (CAP), considered a initial milestone of the Brazilian social security system. Despite this, their struggles were often disregarded by historiography, and few scholars were concerned with investigating the participation of workers in the historical process of shaping this system. As a result, this story ended up asserting itself through explanations outside the experiences and conceptions of the workers themselves, in perspectives that tend to highlight the protagonism of certain political and business leaders. On the other hand, this thesis seeks, in dialogue with historiographical studies on the worlds of work of the period, to understand the experiences that supported the strategies adopted by EFCB workers in the fight for this and other rights. Permanently relating to both public authorities and other professional categories, these workers asserted themselves as active subjects in the process of affirming workers rights during the period. To accompany it, this thesis focuses on the struggles and mobilizations of employees of the Central do Brasil Railroad in Rio de Janeiro between 1865, when the railroad was nationalized, and 1922, when the Caixa de Pensões do Pessoal Jornaleiro of the company was instituted.