In the wentward we can see at left the speed gauge (everything is okay here) but at left there is a gauge with the same size but i don't understand what it say, it never moves or change, it looks like a boost gauge but that don't move :/ Someone can explain what this gauge mean ? (i don't have pics sorry)
That gauge is the air pressure gauge, it shows you how much PSI is in the pneumatic system that would be used for the brake and kneeling functions of the bus.