Deepening economic and social processes in the information environment on the one hand determine the need for timely development, and, on the other hand, provide an opportunity to introduce modern digital methods in the field of assessment and justification of effectiveness of investments in infrastructure facilities. Developing a railway network in difficult geographical conditions and remote areas involves significant investments, long construction time, and is accompanied by a high degree of uncertainty, which is why the study is relevant. The study presents a model of socio-economic assessment of effectiveness of investment for construction of promising railway lines, taking into account the uncertainty of the main dynamic parameters of the project. A cumulative criterion has been developed for assessing the socio-economic efficiency of investments, taking into account the uncertainty for the period of commissioning of the railway line. Analysis of uncertainty factors is carried out. The volume and cost of sales of the main goods transported by the railway line, as well as changes in migration inflow of the population for its service were chosen as the key factors. We have developed probabilistic model of cash flows, effects, results and costs in terms of the payback period of investments, taking into account uncertainty factors for the Monte Carlo method. We have introduced an algorithm of probabilistic assessment of socio-economic efficiency taking into account uncertainty of key parameters of the project by the Monte Carlo method. We have calculated the estimate of socio-economic efficiency taking into account the uncertainty factors of the construction of the railway line. The model of socio-economic assessment of investment efficiency with uncertainty reflects the specifics of the investment project and takes into account the probabilistic uncertainty factors, which provides more accurate and reliable estimate results than deterministic estimate. The results of the study showed that the volume and cost of goods at the time of commissioning of the railway line have the greatest effect on the performance indicators. The factor of migration inflow of population in the area of construction of the line has a minor impact. Due to high rate of return on investment, the investment performance indicator is more sensitive to selected factors in the early stages of assessment (up to 10-15 years). Furthermore, the payback period for the regional level, as well as the level of the enterprise is more sensitive than the payback period at the federal level. The results of socio-economic assessment of efficiency of the investment project showed high efficiency, quick payback and social significance of the project.