The Central Museum of Railway Transport of Russia is situated in St. Petersburg University of construction and means of communications. The museum collections reflect the history of all components of railway transport: locomotives and carriages; communication, automation and means structures. There are unique functioning models of steam engines, carriages, bridges, focusing on construction in Russia and the former USSR.
Photo by RZD website
The museum boasts detailed models, for example a cargo station with railway cars which move up and down a hill. The models of the carriages from the early 20th century opens anyone's eyes who have travelled on an overnight train in Russia recently; these carriages are equipped with a piano salon and even a bathtub.
There are some of the oldest railway collections in the world here, so for anyone with an interest in trains and railway transport this should be on your list of what to see in St. Petersburg.