model train enthusiast; model railroader
Colloquial term for a person who is passionate about model trains, often used in hobbyist communities.
He's a model train enthusiast and spends every weekend building model railways.
Compound of 模型 (model) and 鉄, a slang abbreviation of 鉄道 (railway). The 鉄 suffix is commonly used in enthusiast subculture to denote a fan of a particular railway-related hobby.