The only surviving Y-class locomotive resides far from home, in the National Transportation Museum in St. Louis, Missouri. When I'm King of the World---with apologies to James Cameron---Y6a #2156 will be returned to her proper place with #611 and #1218 under the Claytor Pavilion at the Virginia Museum of Transportation.That might be the last Y6 intact (I saw pictures of the two in a Roanoke scrapyard in Trains in the late 1960s; if you want to talk about steam engines that got away, a picture in Trains sometime in the late 1950s or early 1960s had a North Western E-4 Hudson, which looks a lot like a Hiawatha but not quite as fast in ore-thawing service at Escanaba, Michigan.)
As far as that "only," that refers to the only Y-6. In Cold Spring Shops's back yard is a Y-3, No. 2050.
Mallet Compound at Illinois Railway Museum.
The locomotive was shunted outside for these pictures, ordinarily it is under roof in the building that also houses the big electric locomotives and the Nebraska Zephyr.