215.105—Defective axle.
         A railroad may not place or continue in service a car, if—
    
    
    
    
    
    
        
        (c) 
         An axle on the car, used in conjunction with a plain bearing, has an end collar that is broken or cracked;
    
    
        
        (d) 
         A journal on the car shows evidence of overheating, as evidenced by a  pronounced blue black discoloration; or