
The top rail is the uppermost horizontal member of a window sash, forming the head of the frame that holds the glass panes in place. In sash windows, it’s a critical structural component-often featuring horns in Victorian and Edwardian designs to reinforce the joint with the stiles.
During restoration, preserving or accurately replicating the top rail’s profile, thickness, and detailing is essential for both authentic appearance and smooth operation within the box frame.


