THE MECHANICS CORNER

Through the History of Railroads in the United States a big change has taken place in Brake Systems. From the days of Brakemen climbing from car to car setting individual hand brakes to now with the Latest System using Fiber Optics, and Computers to Control Braking actions.

At first there was only the individual cars handbrake that had to be set and adjusted, as trains descended grades. In snow or Ice you can Imagine the life expectancy of a Brakeman. It was a dangerous job to say the least even in good weather, as the Brakeman went from the roof of one car to the next, setting each Handbrake. Many runaways happened and as the accidents and deaths continued to rise it was necessary to come up with a better way to stop these trains, as they kept getting longer and longer.

About this time along came the Westinghouse Co. and organized the Westinghouse Air Brake Co. They invented the Automatic Brake Valve, which permitted air through a hose to connect all cars, with each car having its own brake valve. Oh what a relief for the Brakeman who no longer had to set each Handbrake individually.

The first brake Valve that I became familiar with was Westinghouse's 24 RL. I'm not sure whether this was the first Brake Valve that they used since my Career with Railroads started in 1963. (Maybe someone out their reading this might be nice enough to fill us in on any information about possible earlier Brake Valves).

Most of today's locomotives has 4 different Brake Systems. The Independent Brake which is used on the Engines in a single Consist only, the Parking or Hand Brake according to the locomotive being used, the Automatic Brake Valve, still being produced by Westinghouse (WABCO), and Dynamic Braking, which turns an Engines Traction Motors into individual Generators creating a resistance thus slowing a train down. Of course in the days of Steam Dynamic Braking wasn't possible. (Here again maybe one of our readers might know a little bit about alternative braking on Steam Locomotives if there were any).

Independent Brakes: Only available to the number of Locomotives in a Consist, and works through MU (multiple Engines connected together with all air hoses connected between locos. Independent Brakes work on a 0 to 71 pounds direct air pressure to the Brake Cylinders on Most Locomotives. I say this because if the Engine has Cast iron Brake Shoes the pressure is usually lower. Most Modern Locos have what are called Composition Shoes and are set at 71 Pounds. Earlier locomotives with Cast Iron Brake Shoes are set at around 45 Pounds. Composition Shoes are similar to the Brake Pads, or Shoes on your Automobile.

Automatic Brakes: This is the main Braking system on a train. Its carried from one end of the train to the other. Automatic Brake Valves work on a reduction system, that is if the system carries 90 pounds and you reduce the pressure or make a "set" of 10 pounds, on the lead Locomotive the brake cylinders on the other locomotives and cars will usually have a Brake Cylinder Pressure of about 22 pounds against the wheels. This is done through the Brake Valve on each Car or Locomotive. Automatic Brakes have to "charge up" before they can be used, that is you cant just start a locomotive up and use the system right away. Charging is accomplished by letting the Automatic Brake Valve sit in a released position for several minutes. Most Locomotives Automatic brake valves are set for 110 pounds for Passenger and 90 pounds for freight.

The newer Westinghouse Automatic Brake Valves are called 26 L's. The improvements include a better operating valve, with needed improvements in operation, a lot more compact unit, an easier unit to work on and service. A 24rl Brake Valve can be seen in my interior Cab shot of the CF-7. Compare that with the Modern Counsel of the Coaster Engine with a 26L system.

Next Time: Dynamic Brakes, Parking Brakes, Hand Brakes, and a look at the Compressors that Make the air.