by BNSFdude » Fri Jul 11, 2014 6:49 pm
As per BNSFs ABTH (air brake and train handling) manuals, they prefer dynamic braking as the method to slow trains down unless the dynamic braking effort is not enough to control train movement speed.
The two can be mixed, and are regularly so on commuters (search Blended Braking). The air brakes are typically used to bring the train to a stop, as dynamics "fade" as you get below 12-15 mph.
Anthony Wood
Audio Engineer - Searchlight Simulations