on the San Bernardino route, the combo lever in the loco and the cab car is not working properly. The throttle works but the brake doesn't work. I have to use the automatic brake to stop the train. How can I fix the problem or is it a bug?
Dynamic brakes are not designed to stop a train, the slower the train gets the more effectiveness dynamic brakes lose because the momentum of the train gets smaller and smaller. In the end, you will always need the automatic brakes to stop the train.
This isn’t a combined power and brake control like those found in a lot of other trains. The braking isn’t full braking but only the dynamic brake function for the loco and is mainly for maintaining speed on a downhill grade, not for use as the main brake for the train.