According to the TGV user manual, the driver "can use the backup brake lever" if the electronic communication between the normal braking system and the carriages doesn't function (page 23). In Train Sim World 2, the backup brake lever isn't funtional (page 16). 根据TGV的用户手册，如果正常的制动系统和车厢之间的电子通讯不工作，司机 "可以使用备用制动杆"（第23页）。在《火车模拟世界2》中，备用制动杆不起作用（第16页）。
So, is the backup braking automatically put into operation after the train braking fails, or does the driver need to manually switch?
