Wiktionary
railfan
n. A railway enthusiast.
Wikipedia
Railfan
A railfan, rail buff or train buff ( American English), railway enthusiast or railway buff ( Australian/ British English), trainspotter or anorak (British English), or foamer (pejorative for American railroaders), is a person interested in a recreational capacity in rail transport. Railfans of many ages can be found worldwide. Railfans often combine their interest with other hobbies, especially photography and videography, radio scanning, model railroading, studying railroad history and participating in train station and rolling stock preservation efforts. Magazines dedicated to railfanning include Trains and Railfan & Railroad.