The Gyermekvasút (English: 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 Uttörővasút (Pioneer Railway, in reference to the communist scouts), and now the official designation is MÁV Zrt. Széchenyi-hegyi Gyermekvasút. Except the train driver, all of the posts are operated by children, beside adult supervision.
The first section, from Széchényi Hill to Előre station (now Virágvölgy) was inaugurated on July 31, 1948. The second section, to Ságvári-liget (now Szépjuhászné), was completed one year later, and the last section, to Hűvösvölgy, was opened in late August 1950.