"If the notice says 'danger,' you shouldn't pass it."
— Sixteen's friends, Cab Over Wheels, Wilbert the Forest Engine
When Sixteen worked at the steelworks, he worked with other industrial engines who were described by Wilbert as his friends. Unlike Sixteen, they obeyed the rules and never went beyond the "DANGER" notice at the tip. They tried their best to warn Sixteen not to go beyond the "DANGER" notice, to no avail.