"Structure gauge#Accidents" . "sufficient height" . "tunnel's dimensions" . "infrastructure dimensions" . "bridge structure" . "Tunnel clearances" . "clearance outline" . "gauge clearance" . . "structure gauge" . . "design clearances" . "structure" . "tunnel clearances" . "Structure gauge" . "headway" . "Tunnel and station platform clearances" . "height clearance" . "bridges and tunnel clearances" . "restricted clearance" . "too small" . . "low-profile" . "headroom" . "minimum structure gauge" . "overhead clearance" . "tighter" . . . "infrastructure clearance envelope" . "height restrictions" . "Structure gauge \u00A7 Accidents" . "small" . "Clearance" . "minimum clearance" . "low clearance" . . "vertical clearance" . . . "clearance" . "dimensions" . . "size" . "bridge strikes" . "accommodate" . "obstructions" . "limited clearances" . "tight clearances" . "Structure gauge" . "inadequate clearances" . "tunnels" . "infrastructure" . "tunnel clearance" . "bridge clearance" . "width" . "clearances" .