This is to remind staff before a train rescue were to take place. . . . 12-car operation (when one 6-car train immobalised) will only take place after complete coupling had been done. Then only the service brakes be released on the defective train. In a 12-car operation, only the rescue train controls the traction, but not brake applications on defective 6-car set. There will always be a brake application (parking brakes) on the defective train, in case the "train breaks away" or pre-mature uncoupling.