There has been a set of gallopers there for a number of years but they were privately owned and contracted into the museum. I understand that the owner retired at the end of 2008 season and was unable to get a successor, so the carousel was dismantled and removed. I'm told that it was later advertised for sale in "Old Glory" and, presumably, elsewhere. The museum did try to negotiate an alternative period ride but negotiations failed to produce a result. It's a pity because the carousel was always very popular and we are still regularly asked when it will be replaced.
There are photos of it on the following:-
http://www.flickr.com/photos/23689245@N08/2784254463/
http://www.flickr.com/photos/23689245@N08/2362142312/
http://www.flickr.com/photos/23689245@N08/2499271721/
Note: the Showman's Engine in the third photograph was a passing visitor and nothing to do with the carousel.