Train Air Brakes.

[CShaveRR]

In our yard, it’s “yard air” and “spotting for air”. But Ed’s telling it straight (with that Texan accent!).

[zapp]

Even with a “yard air” test being done, when we tack on the power when still do a set and release. I would like to know everything is working before I leave the yard.

[broncoman]

[quote]
QUOTE: Originally posted by HighIron2003ar

QUOTE: Originally posted by BentnoseWillie

QUOTE: Actually that is only half right.

18 wheelers use a air compressor to generate air which is filtered and sent to the dry tank. That tank is the supply for the braking system.

On each of the 10 wheels (Not 18 -remember we are dealing with duals on a wheel) the brake pads (Or discs) are applied using air pressure to remove force from a spring that is extremly powerful.

There is a spring inside the chamber that always “Wants” to apply the brakes. If you over come the pressure with sufficient air you will release the brakes.

Oops. Guess I know more about train brakes than truck brakes…[;)]

I dont know much about train brakes =) But I do know a “Big Hole” when I hear one.

You know those air line couplings that auto mechanics use for thier air tools? "**SNap wheiiirr! We have the same thing in specific areas on trucks. The tow driver simply brings a 100 foot coil of hose and connects the dead truck to his own rig’s air system. Presto both have brakes.

I understand that different forms of towing might not actually have functional brakes on the towee but I leave the fine points to the towers to tell.

I heard tell of a friend who suffered a break in his air line. he simply stripped a bic pen down to the plastic tube, put both ends of the severed rubber hose that supplies the air onto it, clamped it and off he went.

Upon review of the writing I used the term “Dry tank”

here is a twist on the dry air and wet air. Air is taken in and used by the compressor to generate a charge in the holding tank. Ideally you want this air to pass thru the wet tank, to the filter and finally to the dry tank.

The wet tank fills over time with oil, grease, sludge and well… water. Ideally you drain this out nightly while you sleep. Fail

[Anonymous]

A lot of mixed information is posted here and a lot of slang terms. There is a lot to understand on freight brakes. The amount of brake pipe reduction is controlled by an equalizing reservoir in the locomotive brake valve. The minimum reduction is approximately 6 - 8 on 26L brake equipment but 5 1/2 - 7 on 30ACDW. This does not give 15 psi in the brake cylinders on a train. While it is normally true that the brake pipe reduction will result in approximately 2 1/2 X reduction to get the brake cylinder pressure, on a minimum reduction it must travel the length of the train to ensure all the brakes are applied. This usually means compensating for leakage and brake pipe restrictions on a long train. Your minimum application will result in approximately 10 psi in the brake cylinder. Enough to set the shoes against the wheels on all cars and locomotives in the consist.
For a better understanding of train brakes contact Wabtec for training classes. Wabtec (ne. WABCO, Westinghouse Air Brake) has classes and training manuals available on line.