except in real life, in the US at least, the dynamic brake does not work like it does in Trainz. its got its own lever that slides (not notches - Trainz makes it seem like a toggle switch) and turns the magnetic field resistance in the traction motors on the wheel axles into a braking power. this of course generates excess electric power which is either returned to batteries or electric supply or is given off as heat through a resistor grid. this does not involve the prime engine (Trainz makes it seem this way).