A survey of the terrestrial snails and slugs along the eastern part of the railway track Hoorn-Alkmaar revealed the presence of 20 different species: 14 species of snails and 6 species of slugs. Only at one locality, the viaduct under the highway A-7, significantly more species were encountered on the “warm” northern slope than on the “cold” southern slope. Noteworthy was the complete absence of xerothermic species belonging to the genera Candidula and Cernuella especially near the viaduct, since several species are living nearby along the highway in southwestern and northeastern direction.