These are things which should be continually kept in mind.
Air Brakes.
The air-brake has changed engine driving materially in the last few years, and a word or two concerning it should be said.
The air-brake consists briefly of an air cylinder placed beneath each car, which can be operated by the engineer from the foot plate, the pressure of the air controlling the action of the brakes.
There are two valves to an air-brake, one for ordinary stops and the other for sudden stops in case of emergency.
In the first only partial pressure of the confined air is used, in the latter the full pressure is employed and the brakes brought against the wheels with all force at once.
One of the most important duties of an engineer is to be well assured that the air-brakes are in proper working order.
After the call for hand brakes has been given, the air brakes must not be applied until the hand brakes are released. Air and hand brakes should never be used at the same time on a car.
When cars having different air pressures are coupled together the brakes will work first on that having the highest pressure.
Special instruction is needed to fully comprehend the working of air brakes.