The purpose of the studies was to assess environmental contamination alongside railway lines in the suburbs of Warsaw by determining the concentrations of selected heavy metals in surface layer of soil as well as moss (Pleurozium schreberi). The studies were conducted in the southern part of Warsaw (central Poland) in three sampling points: before the railway station, and after the station to the northbound. Soil and moss samples were taken from each of these sites at distances of 1, 10, 20 and 30 m from the railroad. Heavy metals were analyzed using flame atomic absorption spectrometry (AAS). The highest Cu, Zn, Ni, and Pb contents in soil were found 1 m from the railroad at each of the analyzed sites. pH was lowest at 30 m (sampling points A and B), and highest at 1 m whilst EC value was highest in sampling point A (near railway station). Maximum contents of heavy metals (Cu, Zn, Ni) in Pleurozium schreberi moss were most often present in the direct proximity of the railroad tracks. ...