The estimated exhaust emissions from railway vehicles in Turkey were presented. The emissions of nitrogen oxides (NO X ), hydrocarbon compounds (HC), carbon monoxide (CO), particulate matter (PM), sulfur dioxide (SO2) and carbon dioxide (CO2) from the diesel locomotives and railcars were calculated using the railway traffic data recorded by Turkish State Railways (TSR) for the period of 2000–2005. EPA emission factors were used for different vehicle types and operation modes such as shunting and line-hauling. Total emissions from railway vehicles in Turkey were estimated as 384 t y−1 for HC, 1016 t y−1 for CO, 6799 t y−1 for NO X , 256 t y−1 for PM, 357 t y−1 for SO2 and 383 537 t y−1 for CO2 for the year 2005. The distribution of emissions with respect to type of railway vehicles shows that the mainline locomotives contribute ∼91% to the total emissions. The increases of 22%, 39% and 49% in the current numbers of mainline locomotives, shunting locomotives and diesel railcars, respectively corresponding to the full capacity of railway network in Turkey will increase the annual emissions to 431 t y−1 for HC, 1121 t y−1 for CO, 7399 t y−1 for NO X , 342 t y−1 for PM, 552 t y−1 for SO2 and 420 256 t y−1 for CO2. Total railway emissions constitute 0. 15%, 0. 08% and 4. 21% of total Turkish traffic emissions for HC, CO and NO X , respectively. [Copyright &y& Elsevier]