There are considered the regression models which describe rail freight conveyances of the members-countries of the European Union. The models contain such factors for each country as: total length of railways, gross domestic product per capita in Purchasing Power Standards and so on. All calculations were performed on the basis of the statistical data taken from EUROSTAT YEARBOOK 2005. Two estimation approaches were compared: the classical linear regression model and the single index model. Various tests for hypothesis of explanatory variables insignificance and model correctness have been carried out, and the cross-validation approach has been applied as well. The analysis has shown obvious advantage of the single index model.