The Gyermekvasút (Children's Railway) or Line 7 is a narrow gauge railway line in Budapest, which connects Széchényi-hegy and Hűvösvölgy and is 11.2 km long. The former name of the line was Úttörővasút (Pioneer Railway, in reference to the communist scouts), and now the official designation is MÁV Zrt. Széchenyi-hegyi Gyermekvasút. Except for the train driver, all of the posts are operated by children aged 10–14 under adult supervision.It is the world's largest Children's Railway.Loco Mk45-2004 is seen entering Széchényi-hegy on 5th June 2014.