Related Clues:

• Revolver in a subway
• Fence-crossing spot
• Underground gate
• Ballpark entry device
• Metro access, and a hint to the circled letters in 17-, 28-, 34- and 43-Across
• Metro-station entrance
• Way over a hedge
• Steps that a farmer might take
• It turns a lot in rush hour
• Subway access
• Way through a fence
• Set of steps in a fence or wall
• It's up to the French to get over it
• 'E lits, perhaps, where you pay on the way in
• How E lit S to let one in