After having cleared formalities and climbing the steps up from the subway into Swindon Works there was invariably an ex-works locomotive waiting to greet visitors at the turntable and on this day it's 5999 Wollaton Hall ready for "running-in" on local services before returning home to Taunton depot.
There is a collection of what I think are eccentric bearings on the left and the notice requires that a clear path be maintained around the turntable, not to prevent excited young visitors from falling in, but to allow engine crew room to push the turntable round!