229.55—Piston travel.
        
        (a) 
         Brake cylinder piston travel shall be sufficient to provide brake shoe clearance when the brakes are released.
    
    
        
        (b) 
         When the brakes are applied on a standing locomotive, the brake cylinder piston travel may not exceed 1 1/2 inches less than the total possible piston travel. The total possible piston travel for each locomotive shall be entered on Form FRA F 6180-49A.