We developed a railway total simulator that can simulate not only each sub system such as a train, signalling system, and power supply system but also train operation and energy usage based on the collaboration of subsystems for all railroads. The purpose of this simulator is to determine the influence of the energy consumption of trains and substations depending on the change in train characteristics, timetables, power supply systems and so on. The targets of calculation for this simulator are the energy consumption of substations and trains restricted by the condition of signalling systems and traffic control systems. We evaluate the simulation accuracy of the proposed simulator for a DC feeding system by using measurements obtained from the Okinawa Urban Monorail. It is confirmed that the simulation results can help predict power behaviour with a sufficient accuracy on railway lines and the average simulation differences were within 6%, namely a 3.6% difference in rolling stock power consumption, 3.9% difference in rolling stock regenerative power, and 3.0% difference in substation power supply. On comparing the calculation results of the proposed simulator with actual measurement data from a general DC power railway system, it is concluded that the simulator and actual results have a sufficiently low difference.