Mellat Park , literally the Nation Park, is an urban park in northern Tehran, Iran. It is one of the city's largest green spaces, situated adjacent to Valiasr Street at the foot of the Alborz mountains to the east, extending to Chamran Expressway and Seoul Street to the west. The park lies in the southern grounds of Tehran International Fair and the Enghelab Club. It is home to one of the first musical fountains in Tehran. Before the 1979 Revolution, it was known as the Imperial Park. It is also the location of a steam-powered locomotive used on Iran's first railway section, built between 1886 and 1888. The locomotive was built by Belgian group Ateliers de Tubize, commissioned in 1887.