> Yes,you are absolutely correct ... BUT if
> you are running passenger cars in freight
> mode you cannot take advantage of the
> graduated release ...took us a while to
> catch on to that. So far the modified 26
> system (no supression etc.) on ge13031 has
> been trouble free.

You can graduate a 26 brake in freight position. When a graduation is desired move the brake valve to release. As the equalizing pressure increases to the desired pressure move the valve back to the reduction zone which will lap the valve. A little different but it has worked.

Robby


epsw271@aol.com

> You can graduate a 26 brake in freight
> position. When a graduation is desired move
> the brake valve to release. As the
> equalizing pressure increases to the desired
> pressure move the valve back to the
> reduction zone which will lap the valve. A
> little different but it has worked.

It might work on passenger cars equipped with graduated release, but for any modern car's valve set up in direct release, it's not going to work ... and you'd be asking for trouble if you made a habit of trying it.

All it takes is one car to sense a slight increase in pressure, and it's going to release the brakes. Since nearly all cars are now equipped with accelerated release systems (where a portion of the emergency reservoir is dumped back into the brake pipe to raise the trainline pressure faster and propogate the release of the brakes), it will be a domino effect once one car moves to release.

Fiv4HghStk@aol.com

> It might work on passenger cars equipped
> with graduated release, but for any modern
> car's valve set up in direct release, it's
> not going to work ... and you'd be asking
> for trouble if you made a habit of trying
> it.

> All it takes is one car to sense a slight
> increase in pressure, and it's going to
> release the brakes. Since nearly all cars
> are now equipped with accelerated release
> systems (where a portion of the emergency
> reservoir is dumped back into the brake pipe
> to raise the trainline pressure faster and
> propogate the release of the brakes), it
> will be a domino effect once one car moves
> to release.

I think he was referring to using a 26-C automatic brake valve set for FRT on a passenger train set up for graduated. I've tried this, and it's very crude and clumsy (if the 26-F control valve on the locomotive isn't set up for graduated, it won't do so).

Just about all 26 control valves have a graduated/direct release cap: 26-C (passenger car) and 26-F (locomotive).

COTS on a 26 system is definitely cheaper than 24-RL. It can take 8 hours to test every component for a single locomotive equipped with a 24-RL system on a test rack.

With the 26 system, there is a 26-F control valve on locomotives, a 26-C valve on cars, and a 26-C automatic brake valve in the cab of a locomotive. It can get a bit confusing. There are other varieites of both valves, but these are the most common.

> I think he was referring to using a 26-C
> automatic brake valve set for FRT on a
> passenger train set up for graduated. I've
> tried this, and it's very crude and clumsy
> (if the 26-F control valve on the locomotive
> isn't set up for graduated, it won't do so).

Situation: ge13031 coupled to two LIRR coaches.
Question: In "pass" mode I am able to vary the brake line pressure up and down easily and quickly. Is the pressure actually applied to the brake shoes on the passenger cars varying by the same amount given a time lag for pressure changes and mechanical movement? It seems altogether too easy to come to a stop from a 12lb reduction changing to a 6lb reduction keeping the train stretched and nailing my stop point with the independent.



lamontdc@adelphia.net

> It might work on passenger cars equipped
> with graduated release, but for any modern
> car's valve set up in direct release, it's
> not going to work ... and you'd be asking
> for trouble if you made a habit of trying
> it.

> All it takes is one car to sense a slight
> increase in pressure, and it's going to
> release the brakes. Since nearly all cars
> are now equipped with accelerated release
> systems (where a portion of the emergency
> reservoir is dumped back into the brake pipe
> to raise the trainline pressure faster and
> propogate the release of the brakes), it
> will be a domino effect once one car moves
> to release.

Any car in direct release should not graduate. Any car in Graduate should graduate. I have observed that it is possible with a 26 brake valve in freight position you can graduate the bakes provided the cars themselves will graduate. My preference is a 24 or 6 brake valve because I determine the ninimal reduction. I have ran trains where UC brakes applied on a 4 lb reduction. A Six puond minimum created too much drag.

Robby


epsw271@aol.com

> Any car in direct release should not
> graduate. Any car in Graduate should
> graduate. I have observed that it is
> possible with a 26 brake valve in freight
> position you can graduate the bakes provided
> the cars themselves will graduate. My
> preference is a 24 or 6 brake valve because
> I determine the ninimal reduction. I have
> ran trains where UC brakes applied on a 4 lb
> reduction. A Six puond minimum created too
> much drag.

Excellent points, Robby. As our air brake instructors once told prospective engineers, there's some old timers out there who will swear up and down that they can get a graduated release on direct release freight equipment. They then lectured the class to "not try it." :-)

I also agree on the 24/6 assessment in regard to minimal reductions. Sometimes 6 pounds is too much, especially if you're shoving a long string of cars with a rider on the rear of the move. Of course, it's a moot point with most modern freight car brakes now, as they've taken the individuality out of train handling.

The way RR train handling practices have evolved over the years, I often have to wonder if it's really progress or not!

Fiv4HghStk@aol.com

> The way RR train handling practices have
> evolved over the years, I often have to
> wonder if it's really progress or not!

Just have some sympathy for us schleps that do this as a "hobby". Short trains, low speeds, short runs, infrequent operations etc. we just don't get the train handling opportunities of a professional. We still have the safety responsibilities and some pride in a smooth operation. To me there is a certain fascination watching a pro handle a train.

lamontdc@adelphia.net

> Situation: ge13031 coupled to two LIRR
> coaches.

What barke system do these cars have?

> Question: In "pass" mode I am able
> to vary the brake line pressure up and down
> easily and quickly. Is the pressure actually
> applied to the brake shoes on the passenger
> cars varying by the same amount given a time
> lag for pressure changes and mechanical
> movement?

The actual numbers for the brake shoe force are a related to the brake cylinder pressure and the leverage ratio of the car. This is typically in the range of 9 to 1 for passenger cars, which translates into 9 inches of brake piston movement = 1 inch of shoe movement (a 9" piston travel is condemnable by the way, this is just to illustrate how the ratio works without resorting to fractions). To calculate the precise forces at the shoes is a complicated process. But, yes, when you graduate off, the brake cylinder pressure reduces, which causes the brake shoe force against the wheel to go down.

> It seems altogether too easy to
> come to a stop from a 12lb reduction
> changing to a 6lb reduction keeping the
> train stretched and nailing my stop point
> with the independent.

I'm not exactly sure what you're describing here. How fast are you going to begin with? A 12 psi reduction is a fair amount, espcially at speeds less than 15 mph. I use it for things like slowing from 79 to 60, stations stops at 40 and less, etc.

You should "nail the stop point" by manipulating the throttle, not the independent. In otherwords, make the train drag the locomotive to a stop (and drag the train to the spot you want it, gently). After the train stops, back off the throttle to run 1, then apply the independent, and when it's fully applied, shut off the throttle.

> Excellent points, Robby. As our air brake
> instructors once told prospective engineers,
> there's some old timers out there who will
> swear up and down that they can get a
> graduated release on direct release freight
> equipment. They then lectured the class to
> "not try it." :-)

They're not getting "graduated release", they're getting "sticky AB valves". On the other hand, you can do this after a fashion so to speak, but you waste a lot of air.

> I also agree on the 24/6 assessment in
> regard to minimal reductions.

Er, well, ah, the only problem with this assessment is that, when they go through Quick Service, the valves on the cars make a 6 psi redecution all by themselves. This is "preset at the factory" and applies to all freight equipments since K and passenger equipments at least since LN. It takes only a 1 1/2 psi reduction to trigger Quick Service.

24 is a lot more expensive to maintain. While I learned on this type of stuff, for passenger trains I prefer a 26-C valve (and not 30-CDW).

> Sometimes 6
> pounds is too much, especially if you're
> shoving a long string of cars with a rider
> on the rear of the move.

Not to be annoying, but,,, what if you're shoving 50 or 60 cars without the air??

> Of course, it's a
> moot point with most modern freight car
> brakes now, as they've taken the
> individuality out of train handling.

How?

One point not mentioned here is the 26NL conversion that can be done to either a #14EL or #6 equipped locomotive. It is one of the easiest things to do with a minimum of fuss because the 6N (or even the 6K) distributing valve is retained. I performed such a conversion to our RS-1 and it only took a couple days of not even full time work on it.

Another point made by mistake here pertains to minimum reductions and the 26 valve vs passenger brakes. So long as the cars are not equipped with a quick reduction feature, then you CAN get less than a 6# off of a 26... Just don't pull the handle all the way to the initial reduction stop.

I also find the comments about graduated vs non-graduated cars and locos a bit amusing. Much of the conversation sounds like there was no such thing as graduated release before 24RL and 26 came along. Most certainly there was but it was done amnually with the automatic brake valve moving from release to lap to service back and forth. Back then it was a SKILL... Not like today where it is taken for granted.

sjwhitney@adelphia.net

Scott, if you equip a locomotive with a 26-NL system that is strictly non-MU consisting of a 26C Brake Valve with 3 position pilot cut-off cock, an H-5-B Relayair valve, a 6N Distributing valve and a 24C Double Check Valve can you set the brake valve to "PASS" position and obtain a graduated release from passenger equipment or are additional portions required?
John J. Blair
"


jjbx@twcny.rr.com

> Scott, if you equip a locomotive with a
> 26-NL system that is strictly non-MU
> consisting of a 26C Brake Valve with 3
> position pilot cut-off cock, an H-5-B
> Relayair valve, a 6N Distributing valve and
> a 24C Double Check Valve can you set the
> brake valve to "PASS" position and
> obtain a graduated release from passenger
> equipment

Yes. Whether or not a car can graduate a release is dependent on the set-up of control/triple valve on the car, not any equipment on the locomotive. To get the car to graduate a release depends on how you manipulate the engineer's brake valve on the locomotive (there are of course configuration considerations with 26-C and 30-CDW brake valves).

> or are additional portions
> required?

No

> John J. Blair

The capability for a 26-C engineer's brake valve to graduate a release depends upon when air pressure is re-admitted to the brake pipe. This is internal to the valve itself, and in FRT, air is not re-admitted to the brake pipe until the handle is placed all the way over to the Release position.

"Converting" a 26-C brake valve to graduated release (can be done in less than a minute using the right tools without depressurizing the system) allows the cut-out valve spool to move to a position which is blocked off when set for FRT. This position permits air to be re-admitted to the brake pipe as soon as the handle is movmed toward Release, in direct proprotion to the amount of handle movement (IOW, the exact opposite of what happens when applying the brakes). The distributing valve (6N-1, 26-F, whatever), 24-C double check valve, Relayair valve, etc. have nothing whatsoever to do with this, other than operate the brakes on the locomotive in response to the manipulation of the 26-C brake valve.

>Another point made by mistake here pertains to minimum reductions and the 26 valve vs passenger brakes. So long as the cars are not equipped with a quick reduction feature,

The term is "Quick Service". There is /no such thing/ as "quick reduction", unless you're referring to Emergency, which is called "Quick Action".

>then you CAN get less than a 6# off of a 26...

You might be able to reduce the equalizing reservoir by less than 6 psi, but the triple and control valves will reduce the brake pipe by 6 psi, period. There is *no* getting around this 6 psi Quick Service reduction unless you make an initial reduction which is greater than 6 psi. Quick Service is preset at the factory, and there isn't any way to remove it. Quick Service has been a specification required by the MCB (now AAR) for triple/control valves since the early 1890s, being adopted as a result of the Burlington tests in the 1880s.

IOW, you *can't* get a less than 6 psi brake pipe reduction unless the triple/control valves on the cars in your train are defective.

In addition, if you reduce the brake pipe by 2-4 psi with any pressure maintaining-equipped engineer's brake valve, and maintaining is cut in and functioning properly, the cars will still make their 6 psi redcution. Then pressure maintaining will try to maintain (raise the brake pipe presssure) because it sees the cars' Quick Service as leakage. The result is that the [train] brakes will release.

>Just don't pull the handle all the way to the initial reduction stop.

Why are you recommending using the equipment in a way it's not designed to? This is a recepie for getting into trouble.