A survey of mammal fauna using a total 26 automatic digital camera traps on an abandoned railway and a series of tunnels belonging to the former Japanese National Railway was conducted from March 2, 2015 to December 19, 2019 in Kasugai, Aichi Prefecture in Central Japan. A total of 74,807 informative photographs were obtained over 41,052 camera days. Of the 15 mammals that were photo-captured, the most frequently photographed was Sus scrofa (relative abundance index: 15.1 photographs/100 camera-days), followed by Paguma larvata (6.2), Felis catus (5.6), Vulpes vulpes (1.4), Nyctereutes procyonoides (1.2), Lepus brachyurus (0.7), Martes melampus (0.2), Procyon lotor (0.2), Capricornis crispus (0.2), Cervus nippon (0.1), Mustela sp. (0.1), Sciurus lis (< 0.1), Macaca fuscata (< 0.1), Meles anakuma (< 0.1), Myocastor coypus (< 0.1), in order. The study area, which is located in the eastern foothills of Aichi Prefecture, supports populations of local wildlife species that are representative of medium- and large–sized mammals (S. scrofa, V. vulpes, N. procyonoides and L. brachyurus, M. melampus, C. crispus, and C. nippon) and is considered to contribute positively towards the conservation of regional biodiversity. Since the activity of S. scrofa and the administrators of the abandoned railway and tunnels overlap during the twilight hours (i.e., one hour before and after sunrise and sunset), caution is necessary to prevent encounters between S. scrofa and humans.