In the San Martín Railway Viaduct, one of the most important railway project carried out in the Autonomous City of Buenos Aires, it was planned the construction of steel strip reinforced soil walls (up to 6 m high), placed over about 6 m of thick soft clay, underlined by a stiff soil. In order to reduce the settlement of the reinforced soil walls and of the track structure, the work started with the construction of controlled density fill piles 50 cm in diameter, founded in the stiff soil layer. Nano-polymeric geocells were used in order to evenly distribute the embankment weight and the railway load to the piles. As the aforementioned solution was failing to meet the project deadline, an alternative solution was studied: the partial replacement of the compressive layer (3 m in depth) and the lay down of two layers of nano-polymeric geocells. A finite element analysis was carried out, and the results showed that the proposed solution did not cause any issues in terms of deformations and settlement of the walls and track structure. Moreover, besides from distributing evenly the load onto the piles, the geocells increased the safety factor related to the global stability analysis; at the same time, the solution allowed the construction company to meet the project deadline.