Railroad Forums
Two independent brake valves?
- Discussion of Electro-Motive locomotive products and technology, past and present. Official web site can be found here: http://www.emdiesels.com/.
Moderator: GOLDEN-ARM
Not absolutly sure but I believe DM&I uses a straight air brake on their freight cars, this in adition to their automatic brake.
If Conductors are in charge, why are they promoted to be Engineer???
Retired Triebfahrzeugführer. I am not a moderator.
Retired Triebfahrzeugführer. I am not a moderator.
That second independent brake valve is for the Orinocco system, which is used as a variable independent brake on the entire train. A second air hose is required, which feeds "straight" air directly to the freight car's cylinders through the exhaust pipe, normally running to the retainer valve. The regular automatic system will still function in the event of a derailment or break in two.
In addition to DMIR, the system was used by EMCO, and originated on the Orinocco iron ore operation in Venezuela, which was operated by US Steel, IIRC.
In addition to DMIR, the system was used by EMCO, and originated on the Orinocco iron ore operation in Venezuela, which was operated by US Steel, IIRC.
NV- (and I'm sure others)
I was ready to start pulling my hair out when I saw your "What was the purpose?" question. Then I gave it some thought and remembered that not everyone reading and contributing to these forums has had "hands on" experience with rail equipment, (some more than others, and many with more experience than mine-). So a VERY basic air brake course follows:
Automatic air brakes (or train air) operates in exactly the opposite manner as one would think. To release the brakes on a train, the engineer charges the brake pipe (or train line), generally to 90 PSI for freight. This charge, through a pretty sophisticated brake valve on each car, fills a reservoir on each car.
When the engineer wants to apply the brakes, a small amount of air is released from the brake pipe. The brake valve, under each car, transfers air from the car reservoir to the car's brake cylinder, and the brakes apply.
In an emergency situation, the automatic air brake fails safe. A break in two, a derailment, or a broken air hose will let all of the air out of the train line, and the brake valve will automatically (hence the name) apply the brakes on every car.
On a railroad with long grades, it is often necessary to apply and release the brakes many times. The problem there is that an engineer can run out of air back in the train, if not careful. Remember that to recharge the reservoirs, you have to release the brakes.
The Orinocco, through the second air hose (and second independent valve) lets the engineer keep a constant pressure on every brake cylinder in the train, even if the automatic brake valve is in release and the train line is being recharged. At EMCO, my understanding is that a seven to ten pound "straight" air application under the train was normal.
The disadvantage is that every car has to be equipped, or at least run in the front of the train. Locomotives have to have the extra brake valve as well. Erie Mining, (which I'm somehow more familiar with then Missabe) had Orinocco valves in all the F-9s, the Centuries and the Geeps. Some of the RS-11s (normally used in the mine) had an extra pipe running underneath so they could trail the road power, which also had dynamic brakes.
Hopefully this explaination answers most of the questions, and doesn't insult anyone.
I was ready to start pulling my hair out when I saw your "What was the purpose?" question. Then I gave it some thought and remembered that not everyone reading and contributing to these forums has had "hands on" experience with rail equipment, (some more than others, and many with more experience than mine-). So a VERY basic air brake course follows:
Automatic air brakes (or train air) operates in exactly the opposite manner as one would think. To release the brakes on a train, the engineer charges the brake pipe (or train line), generally to 90 PSI for freight. This charge, through a pretty sophisticated brake valve on each car, fills a reservoir on each car.
When the engineer wants to apply the brakes, a small amount of air is released from the brake pipe. The brake valve, under each car, transfers air from the car reservoir to the car's brake cylinder, and the brakes apply.
In an emergency situation, the automatic air brake fails safe. A break in two, a derailment, or a broken air hose will let all of the air out of the train line, and the brake valve will automatically (hence the name) apply the brakes on every car.
On a railroad with long grades, it is often necessary to apply and release the brakes many times. The problem there is that an engineer can run out of air back in the train, if not careful. Remember that to recharge the reservoirs, you have to release the brakes.
The Orinocco, through the second air hose (and second independent valve) lets the engineer keep a constant pressure on every brake cylinder in the train, even if the automatic brake valve is in release and the train line is being recharged. At EMCO, my understanding is that a seven to ten pound "straight" air application under the train was normal.
The disadvantage is that every car has to be equipped, or at least run in the front of the train. Locomotives have to have the extra brake valve as well. Erie Mining, (which I'm somehow more familiar with then Missabe) had Orinocco valves in all the F-9s, the Centuries and the Geeps. Some of the RS-11s (normally used in the mine) had an extra pipe running underneath so they could trail the road power, which also had dynamic brakes.
Hopefully this explaination answers most of the questions, and doesn't insult anyone.
This kind of brake-system was in use on a a line with steep gradients in Sweden and Norway in 1912 to 1988.
Is the Orinocco system the same system?