The old Athol roundhouse of the Boston & Albany's Athol Branch is still standing. The branch was abandoned in 1935 at the time of the construction of the Quabbin Reservoir. Curiously, a quarter-mile or so of the rails are still there, long dormant, heading toward the Athol depot which the line shared with the B&M's Fitchburg main. Adjacent to them, next to the B&M, stands the brick roundhouse, which is now used by a local person for storage. It is accessible, to an extent, by car or by foot; the access is a bit hard to find, and it's barely worth the effort. Unfortunately, the building is surrounded by an industrial fence and a lot of junk. While one can walk right up to it, it's actually far better seen from the other side of the B&M. Contact me if you want directions. I don't know whether the turntable pit is still there; if it is, it's not readily visible.