Shunting locomotives at railroad stations account for most emissions of pollutants into the atmosphere. A significant share of these emissions depends on the position of the driver's controller that is used to operate a diesel locomotive, as each position of the controller corresponds to a specific rotation frequency and power of the diesel engine. We have investigated the influence of application of the energy accumulator within a power circuit of a shunting locomotive on the level of emissions of pollutants into the atmosphere when it performs different shunting operations. The relation has been established between the levels of pollutant emission into the atmosphere and the types of shunting operations performed. We have obtained statistical data regarding the time of a diesel locomotive shunting operation at each position of the driver's controller when performing different types of shunting work. That makes it possible to optimally select the parameters of an energy accumulator for a shunting locomotive, which can meet both the technical and environmental requirements. It was established, based on the results from the current study, that using the energy accumulator within a power circuit of a shunting diesel locomotive reduces the amount of emissions of carbon oxide CO, nitric oxide NO х , sulfur dioxide SO 2 , soot and hydrocarbons, into the atmosphere by 20...30 % depending on the type of performed shunting operations and the capacity of the energy accumulator applied. Bringing down the level of specified emissions would make it possible to improve environmental conditions at a station