The latest edition of Steppe Magazine has a marvellous article Notes from Underground: The Tashkent Metro.
The havoc inflicted on the Uzbek capital by a devastating earthquake in 1966, also opened the way for Soviet planners to endow the city with an outstanding transport system. Some of the stations are gems: each has its own theme, reflected in its architecture and art work. Uzbek Journeys tours include a roam around the best stations.
If you're interested in Central Asia, a subscription to Steppe is a must.
Update 8 February 2018: It is now possible to photograph within the Tashkent metro system.
Related posts: Tashkent's Soviet Buildings
Tashkent's Open Air Railway Museum
Travelling by Rail in Uzbekistan
Azerbaijan: Baku's Metro