The capacity and productivity effects of the NRLA are a key requirement for a sustainable transfer process. The construction of a flat rail link on the Gotthard axis allows savings in traction costs and gains in time, thereby improving the competitiveness of freight transport by rail in comparison to freight transport by road. The construction of a 4-metre corridor on the Gotthard axis gives rail freight transport access to additional market segments and improves its productivity. The aim of this study is to assess the impact on the volume of traffic of the commissioning of the NRLA and a 4-metre corridor on the Gotthard axis. To this end, a model was created to simulate the effects of the infrastructure upgrades on various parameters of rail freight transport including productivity, capacity and quality.