This report describes the methodology used in the ARTEMIS rail emissions model. The approached used is a matrix of operating conditions, speeds and accelerations, for which basic parameters are used to calculated the resistance to motion of trains. Four types of resistance are included: rolling, aerodynamic, gravitational and acceleration. A necessary element in the calculation is the driving pattern, that is, the distribution of speeds and accelerations for typical operation.In the report, data are analyzed to provide operation condition distributions on both a spatial and temporal basis. The calculation procedure is evaluated with respect to resolution of operation conditions, and then evaluated by comparison with experimental data for a variety of passenger and goods trains. The results indicate that the energy consumption from modeling approach is valid to better that 10% for known operating characteristics. Emissions are calculated from the energy consumption using average fuel based emissions factors and electrical production emissions factors.