?

The reason I am asking is that there is a car float operation right outside my office windows. There is a level crossing for the yard traffic, not open to the public, that crosses the yard. When loading and unloading the cars off the car float the train only clears the crossing when less than 4 cars are coupled to the engine.

Sometimes the engineer blows the horn and rings the bell when the train is moving across the grade crossing, but most of the time he doesn't. Is he supposed to ring the bell or are those guys just slacking off on their procedures?