This paper follows an electromechanical methodology to estimate the electric load demand for railway systems, applied to Inter-Urban Light Railway Systems, using parametrical models for hourly peak and low demand of the system. Once the electric power consumption is computed for an urban light railway path, it is made the analysis of impact of this electric load on an electric distribution system fully developed, such as it occurs in Colombia, where the railway system is introduced. It is assumed as test distribution system, the IEEE 118 nodes, where it is defined the train path the connection points to the distribution system. After computing the electric load of the train system, load flow and short circuit analysis are made in order to determine the impact on the system.